diff --git a/examples/basic_html.rs b/examples/basic_html.rs
index 7fd5261..d865c35 100644
--- a/examples/basic_html.rs
+++ b/examples/basic_html.rs
@@ -1,5 +1,7 @@
-use lettre::message::{header, MultiPart, SinglePart};
-use lettre::{FileTransport, Message, Transport};
+use lettre::{
+    message::{header, MultiPart, SinglePart},
+    FileTransport, Message, Transport,
+};
 
 fn main() {
     // The html we want to send.
diff --git a/examples/maud_html.rs b/examples/maud_html.rs
index ec92916..17d489b 100644
--- a/examples/maud_html.rs
+++ b/examples/maud_html.rs
@@ -1,5 +1,7 @@
-use lettre::message::{header, MultiPart, SinglePart};
-use lettre::{FileTransport, Message, Transport};
+use lettre::{
+    message::{header, MultiPart, SinglePart},
+    FileTransport, Message, Transport,
+};
 use maud::html;
 
 fn main() {
diff --git a/examples/smtp_selfsigned.rs b/examples/smtp_selfsigned.rs
index 378b032..873d304 100644
--- a/examples/smtp_selfsigned.rs
+++ b/examples/smtp_selfsigned.rs
@@ -1,8 +1,10 @@
 use std::fs;
 
 use lettre::{
-    transport::smtp::authentication::Credentials,
-    transport::smtp::client::{Certificate, Tls, TlsParameters},
+    transport::smtp::{
+        authentication::Credentials,
+        client::{Certificate, Tls, TlsParameters},
+    },
     Message, SmtpTransport, Transport,
 };
 
@@ -20,9 +22,10 @@ fn main() {
     // Use a custom certificate stored on disk to securely verify the server's certificate
     let pem_cert = fs::read("certificate.pem").unwrap();
     let cert = Certificate::from_pem(&pem_cert).unwrap();
-    let mut tls = TlsParameters::builder("smtp.server.com".to_string());
-    tls.add_root_certificate(cert);
-    let tls = tls.build().unwrap();
+    let tls = TlsParameters::builder("smtp.server.com".to_string())
+        .add_root_certificate(cert)
+        .build()
+        .unwrap();
 
     let creds = Credentials::new("smtp_username".to_string(), "smtp_password".to_string());
 
diff --git a/src/address/mod.rs b/src/address/mod.rs
index 765914d..e9818ce 100644
--- a/src/address/mod.rs
+++ b/src/address/mod.rs
@@ -6,5 +6,7 @@ mod serde;
 mod envelope;
 mod types;
 
-pub use self::envelope::Envelope;
-pub use self::types::{Address, AddressError};
+pub use self::{
+    envelope::Envelope,
+    types::{Address, AddressError},
+};
diff --git a/src/lib.rs b/src/lib.rs
index 302a625..957986e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -56,8 +56,6 @@ pub mod transport;
 extern crate hyperx;
 
 pub use crate::address::Address;
-use crate::address::Envelope;
-use crate::error::Error;
 #[cfg(feature = "builder")]
 pub use crate::message::Message;
 #[cfg(feature = "file-transport")]
@@ -77,6 +75,7 @@ pub use crate::transport::smtp::SmtpTransport;
 pub use crate::transport::smtp::Tokio02Connector;
 #[cfg(all(feature = "smtp-transport", feature = "tokio1"))]
 pub use crate::transport::smtp::Tokio1Connector;
+use crate::{address::Envelope, error::Error};
 #[cfg(any(feature = "async-std1", feature = "tokio02", feature = "tokio1"))]
 use async_trait::async_trait;
 
diff --git a/src/message/body.rs b/src/message/body.rs
index dda71b0..ab5f88f 100644
--- a/src/message/body.rs
+++ b/src/message/body.rs
@@ -1,5 +1,7 @@
-use std::io::{self, Write};
-use std::ops::Deref;
+use std::{
+    io::{self, Write},
+    ops::Deref,
+};
 
 use crate::message::header::ContentTransferEncoding;
 
diff --git a/src/message/mailbox/types.rs b/src/message/mailbox/types.rs
index f68cc37..e1a95ee 100644
--- a/src/message/mailbox/types.rs
+++ b/src/message/mailbox/types.rs
@@ -54,7 +54,7 @@ impl Mailbox {
     /// # Examples
     ///
     /// ```
-    /// use lettre::{Address, message::Mailbox};
+    /// use lettre::{message::Mailbox, Address};
     ///
     /// # use std::error::Error;
     /// # fn main() -> Result<(), Box<dyn Error>> {
@@ -163,7 +163,10 @@ impl Mailboxes {
     /// # Examples
     ///
     /// ```
-    /// use lettre::{Address, message::{Mailbox, Mailboxes}};
+    /// use lettre::{
+    ///     message::{Mailbox, Mailboxes},
+    ///     Address,
+    /// };
     ///
     /// # use std::error::Error;
     /// # fn main() -> Result<(), Box<dyn Error>> {
@@ -182,7 +185,10 @@ impl Mailboxes {
     /// # Examples
     ///
     /// ```
-    /// use lettre::{Address, message::{Mailbox, Mailboxes}};
+    /// use lettre::{
+    ///     message::{Mailbox, Mailboxes},
+    ///     Address,
+    /// };
     ///
     /// # use std::error::Error;
     /// # fn main() -> Result<(), Box<dyn Error>> {
@@ -201,7 +207,10 @@ impl Mailboxes {
     /// # Examples
     ///
     /// ```
-    /// use lettre::{Address, message::{Mailbox, Mailboxes}};
+    /// use lettre::{
+    ///     message::{Mailbox, Mailboxes},
+    ///     Address,
+    /// };
     ///
     /// # use std::error::Error;
     /// # fn main() -> Result<(), Box<dyn Error>> {
@@ -225,7 +234,10 @@ impl Mailboxes {
     /// # Examples
     ///
     /// ```
-    /// use lettre::{Address, message::{Mailbox, Mailboxes}};
+    /// use lettre::{
+    ///     message::{Mailbox, Mailboxes},
+    ///     Address,
+    /// };
     ///
     /// # use std::error::Error;
     /// # fn main() -> Result<(), Box<dyn Error>> {
diff --git a/src/message/mimebody.rs b/src/message/mimebody.rs
index 10ea5bc..79c9849 100644
--- a/src/message/mimebody.rs
+++ b/src/message/mimebody.rs
@@ -6,15 +6,12 @@ use mime::Mime;
 use rand::Rng;
 
 /// MIME part variants
-///
 #[derive(Debug, Clone)]
 pub enum Part {
     /// Single part with content
-    ///
     Single(SinglePart),
 
     /// Multiple parts of content
-    ///
     Multi(MultiPart),
 }
 
@@ -37,11 +34,9 @@ impl Part {
 }
 
 /// Parts of multipart body
-///
 pub type Parts = Vec<Part>;
 
 /// Creates builder for single part
-///
 #[derive(Debug, Clone)]
 pub struct SinglePartBuilder {
     headers: Headers,
@@ -92,17 +87,16 @@ impl Default for SinglePartBuilder {
 /// # Example
 ///
 /// ```
-/// use lettre::message::{SinglePart, header};
+/// use lettre::message::{header, SinglePart};
 ///
 /// # use std::error::Error;
 /// # fn main() -> Result<(), Box<dyn Error>> {
 /// let part = SinglePart::builder()
-///      .header(header::ContentType("text/plain; charset=utf8".parse()?))
-///      .body(String::from("Текст письма в уникоде"));
+///     .header(header::ContentType("text/plain; charset=utf8".parse()?))
+///     .body(String::from("Текст письма в уникоде"));
 /// # Ok(())
 /// # }
 /// ```
-///
 #[derive(Debug, Clone)]
 pub struct SinglePart {
     headers: Headers,
@@ -170,7 +164,6 @@ impl EmailFormat for SinglePart {
 }
 
 /// The kind of multipart
-///
 #[derive(Debug, Clone)]
 pub enum MultiPartKind {
     /// Mixed kind to combine unrelated content parts
@@ -257,7 +250,6 @@ impl From<MultiPartKind> for Mime {
 }
 
 /// Multipart builder
-///
 #[derive(Debug, Clone)]
 pub struct MultiPartBuilder {
     headers: Headers,
@@ -323,7 +315,6 @@ impl Default for MultiPartBuilder {
 }
 
 /// Multipart variant with parts
-///
 #[derive(Debug, Clone)]
 pub struct MultiPart {
     headers: Headers,
diff --git a/src/message/mod.rs b/src/message/mod.rs
index 8718541..0ca9e5d 100644
--- a/src/message/mod.rs
+++ b/src/message/mod.rs
@@ -114,7 +114,6 @@
 //!
 //! <p><b>Hello</b>, <i>world</i>! <img src="cid:123"></p>
 //! --0oVZ2r6AoLAhLlb0gPNSKy6BEqdS2IfwxrcbUuo1--
-//!
 //! ```
 //! </details>
 //!
@@ -125,8 +124,8 @@
 //!
 //! ```rust
 //! # use std::error::Error;
+//! use lettre::message::{header, Body, Message, MultiPart, Part, SinglePart};
 //! use std::fs;
-//! use lettre::message::{Body, header, Message, MultiPart, Part, SinglePart};
 //!
 //! # fn main() -> Result<(), Box<dyn Error>> {
 //! let image = fs::read("docs/lettre.png")?;
@@ -236,7 +235,6 @@
 //!
 //! fn main() { println!("Hello, World!") }
 //! --0oVZ2r6AoLAhLlb0gPNSKy6BEqdS2IfwxrcbUuo1--
-//!
 //! ```
 //! </details>
 
@@ -252,8 +250,7 @@ mod mailbox;
 mod mimebody;
 mod utf8_b;
 
-use std::convert::TryFrom;
-use std::time::SystemTime;
+use std::{convert::TryFrom, time::SystemTime};
 
 use uuid::Uuid;
 
diff --git a/src/transport/file/mod.rs b/src/transport/file/mod.rs
index 7ac3347..085ade1 100644
--- a/src/transport/file/mod.rs
+++ b/src/transport/file/mod.rs
@@ -9,8 +9,8 @@
 //!
 //! # #[cfg(all(feature = "file-transport", feature = "builder"))]
 //! # fn main() -> Result<(), Box<dyn Error>> {
+//! use lettre::{FileTransport, Message, Transport};
 //! use std::env::temp_dir;
-//! use lettre::{Transport, Message, FileTransport};
 //!
 //! // Write to the local temp directory
 //! let sender = FileTransport::new(temp_dir());
@@ -41,8 +41,8 @@
 //!
 //! # #[cfg(all(feature = "file-transport-envelope", feature = "builder"))]
 //! # fn main() -> Result<(), Box<dyn Error>> {
+//! use lettre::{FileTransport, Message, Transport};
 //! use std::env::temp_dir;
-//! use lettre::{Transport, Message, FileTransport};
 //!
 //! // Write to the local temp directory
 //! let sender = FileTransport::with_envelope(temp_dir());
@@ -133,14 +133,13 @@
 //! ```
 
 pub use self::error::Error;
-use crate::address::Envelope;
 #[cfg(feature = "async-std1")]
 use crate::AsyncStd1Transport;
 #[cfg(feature = "tokio02")]
 use crate::Tokio02Transport;
 #[cfg(feature = "tokio1")]
 use crate::Tokio1Transport;
-use crate::Transport;
+use crate::{address::Envelope, Transport};
 #[cfg(any(feature = "async-std1", feature = "tokio02", feature = "tokio1"))]
 use async_trait::async_trait;
 use std::{
diff --git a/src/transport/sendmail/mod.rs b/src/transport/sendmail/mod.rs
index 513c1f7..a59157f 100644
--- a/src/transport/sendmail/mod.rs
+++ b/src/transport/sendmail/mod.rs
@@ -96,14 +96,13 @@
 //! ```
 
 pub use self::error::Error;
-use crate::address::Envelope;
 #[cfg(feature = "async-std1")]
 use crate::AsyncStd1Transport;
 #[cfg(feature = "tokio02")]
 use crate::Tokio02Transport;
 #[cfg(feature = "tokio1")]
 use crate::Tokio1Transport;
-use crate::Transport;
+use crate::{address::Envelope, Transport};
 #[cfg(any(feature = "async-std1", feature = "tokio02", feature = "tokio1"))]
 use async_trait::async_trait;
 use std::{
diff --git a/src/transport/smtp/client/async_net.rs b/src/transport/smtp/client/async_net.rs
index fbec4c3..1c70d30 100644
--- a/src/transport/smtp/client/async_net.rs
+++ b/src/transport/smtp/client/async_net.rs
@@ -10,8 +10,10 @@ use std::{
     task::{Context, Poll},
 };
 
-use futures_io::{AsyncRead as FuturesAsyncRead, AsyncWrite as FuturesAsyncWrite};
-use futures_io::{Error as IoError, ErrorKind, Result as IoResult};
+use futures_io::{
+    AsyncRead as FuturesAsyncRead, AsyncWrite as FuturesAsyncWrite, Error as IoError, ErrorKind,
+    Result as IoResult,
+};
 #[cfg(feature = "tokio02")]
 use tokio02_crate::io::{AsyncRead as _, AsyncWrite as _};
 #[cfg(feature = "tokio1")]
@@ -370,8 +372,7 @@ impl AsyncNetworkStream {
 
                 #[cfg(feature = "async-std1-rustls-tls")]
                 return {
-                    use async_rustls::webpki::DNSNameRef;
-                    use async_rustls::TlsConnector;
+                    use async_rustls::{webpki::DNSNameRef, TlsConnector};
 
                     let domain = DNSNameRef::try_from_ascii_str(&domain)?;
 
diff --git a/src/transport/smtp/client/connection.rs b/src/transport/smtp/client/connection.rs
index 38f6f90..b19ef2b 100644
--- a/src/transport/smtp/client/connection.rs
+++ b/src/transport/smtp/client/connection.rs
@@ -6,13 +6,15 @@ use std::{
 };
 
 use super::{ClientCodec, NetworkStream, TlsParameters};
-use crate::address::Envelope;
-use crate::transport::smtp::{
-    authentication::{Credentials, Mechanism},
-    commands::*,
-    error::Error,
-    extension::{ClientId, Extension, MailBodyParameter, MailParameter, ServerInfo},
-    response::{parse_response, Response},
+use crate::{
+    address::Envelope,
+    transport::smtp::{
+        authentication::{Credentials, Mechanism},
+        commands::*,
+        error::Error,
+        extension::{ClientId, Extension, MailBodyParameter, MailParameter, ServerInfo},
+        response::{parse_response, Response},
+    },
 };
 
 #[cfg(feature = "tracing")]
diff --git a/src/transport/smtp/client/tls.rs b/src/transport/smtp/client/tls.rs
index 4885427..54f6b0d 100644
--- a/src/transport/smtp/client/tls.rs
+++ b/src/transport/smtp/client/tls.rs
@@ -65,7 +65,7 @@ impl TlsParametersBuilder {
     /// Add a custom root certificate
     ///
     /// Can be used to safely connect to a server using a self signed certificate, for example.
-    pub fn add_root_certificate(&mut self, cert: Certificate) -> &mut Self {
+    pub fn add_root_certificate(mut self, cert: Certificate) -> Self {
         self.root_certs.push(cert);
         self
     }
@@ -85,10 +85,7 @@ impl TlsParametersBuilder {
     /// Hostname verification can only be disabled with the `native-tls` TLS backend.
     #[cfg(feature = "native-tls")]
     #[cfg_attr(docsrs, doc(cfg(feature = "native-tls")))]
-    pub fn dangerous_accept_invalid_hostnames(
-        &mut self,
-        accept_invalid_hostnames: bool,
-    ) -> &mut Self {
+    pub fn dangerous_accept_invalid_hostnames(mut self, accept_invalid_hostnames: bool) -> Self {
         self.accept_invalid_hostnames = accept_invalid_hostnames;
         self
     }
@@ -109,7 +106,7 @@ impl TlsParametersBuilder {
     ///
     /// This method should only be used as a last resort, as it introduces
     /// significant vulnerabilities to man-in-the-middle attacks.
-    pub fn dangerous_accept_invalid_certs(&mut self, accept_invalid_certs: bool) -> &mut Self {
+    pub fn dangerous_accept_invalid_certs(mut self, accept_invalid_certs: bool) -> Self {
         self.accept_invalid_certs = accept_invalid_certs;
         self
     }
diff --git a/src/transport/smtp/mod.rs b/src/transport/smtp/mod.rs
index 61e47d5..aa4dff8 100644
--- a/src/transport/smtp/mod.rs
+++ b/src/transport/smtp/mod.rs
@@ -43,8 +43,7 @@
 //!     .body(String::from("Be happy!"))?;
 //!
 //! // Create TLS transport on port 465
-//! let sender = SmtpTransport::relay("smtp.example.com")
-//!     .expect("relay valid")
+//! let sender = SmtpTransport::relay("smtp.example.com")?
 //!     .build();
 //! // Send the email via remote relay
 //! let result = sender.send(&email);
@@ -52,107 +51,70 @@
 //! # Ok(())
 //! # }
 //! ```
-
-//! #### Complete example
 //!
-//! ```todo
-//! # #[cfg(feature = "smtp-transport")]
-//! # {
-//! use lettre::transport::smtp::authentication::{Credentials, Mechanism};
-//! use lettre::{Email, Envelope, Transport, SmtpClient};
-//! use lettre::transport::smtp::extension::ClientId;
+//! #### Authentication
 //!
-//! let email_1 = Email::new(
-//!     Envelope::new(
-//!         Some(EmailAddress::new("user@localhost".to_string())?),
-//!         vec![EmailAddress::new("root@localhost".to_string())?],
-//!     )?,
-//!     "id1".to_string(),
-//!     "Hello world".to_string().into_bytes(),
-//! );
+//! Example with authentication and connection pool:
 //!
-//! let email_2 = Email::new(
-//!     Envelope::new(
-//!         Some(EmailAddress::new("user@localhost".to_string())?),
-//!         vec![EmailAddress::new("root@localhost".to_string())?],
-//!     )?,
-//!     "id2".to_string(),
-//!     "Hello world a second time".to_string().into_bytes(),
-//! );
+//! ```rust,no_run
+//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls-tls")))]
+//! # fn test() -> Result<(), Box<dyn std::error::Error>> {
+//! use lettre::{Message, Transport, SmtpTransport, transport::smtp::{PoolConfig, authentication::{Credentials, Mechanism}}};
 //!
-//! // Connect to a remote server on a custom port
-//! let mut mailer = SmtpClient::new_simple("server.tld")?
-//!    // Set the name sent during EHLO/HELO, default is `localhost`
-//!    .hello_name(ClientId::Domain("my.hostname.tld".to_string()))
-//!    // Add credentials for authentication
-//!    .credentials(Credentials::new("username".to_string(), "password".to_string()))
-//!    // Enable SMTPUTF8 if the server supports it
-//!    .smtp_utf8(true)
-//!    // Configure expected authentication mechanism
-//!    .authentication_mechanism(Mechanism::Plain)
-//!    // Enable connection reuse
-//!    .connection_reuse(ConnectionReuseParameters::ReuseUnlimited).transport();
+//! let email = Message::builder()
+//!     .from("NoBody <nobody@domain.tld>".parse()?)
+//!     .reply_to("Yuin <yuin@domain.tld>".parse()?)
+//!     .to("Hei <hei@domain.tld>".parse()?)
+//!     .subject("Happy new year")
+//!     .body(String::from("Be happy!"))?;
 //!
-//! let result_1 = mailer.send(&email_1);
-//! assert!(result_1.is_ok());
+//! // Create TLS transport on port 587 with STARTTLS
+//! let sender = SmtpTransport::starttls_relay("smtp.example.com")?
+//!     // Add credentials for authentication
+//!     .credentials(Credentials::new("username".to_string(), "password".to_string()))
+//!     // Configure expected authentication mechanism
+//!     .authentication(vec![Mechanism::Plain])
+//!     // Connection pool settings
+//!     .pool_config( PoolConfig::new().max_size(20))
+//!     .build();
 //!
-//! // The second email will use the same connection
-//! let result_2 = mailer.send(&email_2);
-//! assert!(result_2.is_ok());
-//!
-//! // Explicitly close the SMTP transaction as we enabled connection reuse
-//! mailer.close();
+//! // Send the email via remote relay
+//! let result = sender.send(&email);
+//! assert!(result.is_ok());
+//! # Ok(())
 //! # }
 //! ```
 //!
 //! You can specify custom TLS settings:
 //!
-//! ```todo
-//! # #[cfg(feature = "native-tls")]
-//! # {
-//! use lettre::{
-//!     ClientSecurity, ClientTlsParameters, EmailAddress, Envelope,
-//!     Email, SmtpClient, Transport,
-//! };
-//! use lettre::transport::smtp::authentication::{Credentials, Mechanism};
-//! use lettre::transport::smtp::ConnectionReuseParameters;
-//! use native_tls::{Protocol, TlsConnector};
+//! ```rust,no_run
+//! # #[cfg(all(feature = "builder", any(feature = "native-tls", feature = "rustls-tls")))]
+//! # fn test() -> Result<(), Box<dyn std::error::Error>> {
+//! use lettre::{Message, Transport, SmtpTransport, transport::smtp::client::{TlsParameters, Tls}};
 //!
-//!     let email = Email::new(
-//!         Envelope::new(
-//!             Some(EmailAddress::new("user@localhost".to_string())?),
-//!             vec![EmailAddress::new("root@localhost".to_string())?],
-//!         )?,
-//!         "message_id".to_string(),
-//!         "Hello world".to_string().into_bytes(),
-//!     );
+//! let email = Message::builder()
+//!     .from("NoBody <nobody@domain.tld>".parse()?)
+//!     .reply_to("Yuin <yuin@domain.tld>".parse()?)
+//!     .to("Hei <hei@domain.tld>".parse()?)
+//!     .subject("Happy new year")
+//!     .body(String::from("Be happy!"))?;
 //!
-//!     let mut tls_builder = TlsConnector::builder();
-//!     tls_builder.min_protocol_version(Some(Protocol::Tlsv10));
-//!     let tls_parameters =
-//!         ClientTlsParameters::new(
-//!             "smtp.example.com".to_string(),
-//!             tls_builder.build()?
-//!         );
+//! // Custom TLS configuration
+//! let tls = TlsParameters::builder("smtp.example.com".to_string())
+//!           .dangerous_accept_invalid_certs(true).build()?;
 //!
-//!     let mut mailer = SmtpClient::new(
-//!         ("smtp.example.com", 465), ClientSecurity::Wrapper(tls_parameters)
-//!     )?
-//!         .authentication_mechanism(Mechanism::Login)
-//!         .credentials(Credentials::new(
-//!             "example_username".to_string(), "example_password".to_string()
-//!         ))
-//!         .connection_reuse(ConnectionReuseParameters::ReuseUnlimited)
-//!         .transport();
+//! // Create TLS transport on port 465
+//! let sender = SmtpTransport::relay("smtp.example.com")?
+//!     // Custom TLS configuration
+//!     .tls(Tls::Required(tls))
+//!     .build();
 //!
-//!     let result = mailer.send(&email);
-//!
-//!     assert!(result.is_ok());
-//!
-//!     mailer.close();
+//! // Send the email via remote relay
+//! let result = sender.send(&email);
+//! assert!(result.is_ok());
+//! # Ok(())
 //! # }
 //! ```
-//!
 
 #[cfg(feature = "async-std1")]
 pub use self::async_transport::AsyncStd1Connector;
diff --git a/src/transport/smtp/pool.rs b/src/transport/smtp/pool.rs
index 92fae3a..18e2e1a 100644
--- a/src/transport/smtp/pool.rs
+++ b/src/transport/smtp/pool.rs
@@ -16,6 +16,11 @@ pub struct PoolConfig {
 }
 
 impl PoolConfig {
+    /// Create a new pool configuration with default values
+    pub fn new() -> Self {
+        Self::default()
+    }
+
     /// Minimum number of idle connections
     ///
     /// Defaults to `0`
diff --git a/src/transport/smtp/transport.rs b/src/transport/smtp/transport.rs
index 912c330..1ea0b5d 100644
--- a/src/transport/smtp/transport.rs
+++ b/src/transport/smtp/transport.rs
@@ -8,8 +8,7 @@ use super::PoolConfig;
 use super::{ClientId, Credentials, Error, Mechanism, Response, SmtpConnection, SmtpInfo};
 #[cfg(any(feature = "native-tls", feature = "rustls-tls"))]
 use super::{Tls, TlsParameters, SUBMISSIONS_PORT, SUBMISSION_PORT};
-use crate::address::Envelope;
-use crate::Transport;
+use crate::{address::Envelope, Transport};
 
 #[allow(missing_debug_implementations)]
 #[derive(Clone)]
diff --git a/src/transport/stub/mod.rs b/src/transport/stub/mod.rs
index 6e66f59..0b27f89 100644
--- a/src/transport/stub/mod.rs
+++ b/src/transport/stub/mod.rs
@@ -9,8 +9,7 @@
 //! ```rust
 //! # #[cfg(feature = "builder")]
 //! # {
-//! use lettre::{Message, Transport};
-//! use lettre::transport::stub::StubTransport;
+//! use lettre::{transport::stub::StubTransport, Message, Transport};
 //!
 //! # use std::error::Error;
 //! # fn main() -> Result<(), Box<dyn Error>> {
@@ -29,12 +28,11 @@
 //! # }
 //! ```
 
-use crate::address::Envelope;
 #[cfg(feature = "async-std1")]
 use crate::AsyncStd1Transport;
 #[cfg(feature = "tokio02")]
 use crate::Tokio02Transport;
-use crate::Transport;
+use crate::{address::Envelope, Transport};
 #[cfg(any(feature = "async-std1", feature = "tokio02"))]
 use async_trait::async_trait;
 use std::{error::Error as StdError, fmt};
diff --git a/tests/transport_smtp_pool.rs b/tests/transport_smtp_pool.rs
index 18154b5..0830a9a 100644
--- a/tests/transport_smtp_pool.rs
+++ b/tests/transport_smtp_pool.rs
@@ -1,7 +1,6 @@
 #[cfg(all(test, feature = "smtp-transport", feature = "r2d2"))]
 mod test {
-    use lettre::address::Envelope;
-    use lettre::{SmtpTransport, Transport};
+    use lettre::{address::Envelope, SmtpTransport, Transport};
 
     use std::{sync::mpsc, thread};