diff --git a/src/directory/mmap_directory.rs b/src/directory/mmap_directory.rs
index d6a6cdbd3..e4e595fec 100644
--- a/src/directory/mmap_directory.rs
+++ b/src/directory/mmap_directory.rs
@@ -99,34 +99,29 @@ impl MmapDirectory {
 
 /// This Write wraps a File, but has the specificity of 
 /// call `sync_all` on flush.  
-struct SafeFileWriter {
-    writer: BufWriter<File>,
-}
+struct SafeFileWriter(File);
 
 impl SafeFileWriter {
     fn new(file: File) -> SafeFileWriter {
-        SafeFileWriter {
-            writer: BufWriter::new(file),
-        }
+        SafeFileWriter(file)
     }
-
 }
 
 impl Write for SafeFileWriter {
 
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        self.writer.write(buf)
+        self.0.write(buf)
     }
 
     fn flush(&mut self) -> io::Result<()> {
-        try!(self.writer.flush());
-        self.writer.get_ref().sync_all()
+        try!(self.0.flush());
+        self.0.sync_all()
     }
 }
 
 impl Seek for SafeFileWriter {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
-        self.writer.seek(pos)
+        self.0.seek(pos)
     }
 }
 
@@ -204,7 +199,7 @@ impl Directory for MmapDirectory {
         try!(self.sync_directory());
         
         let writer = SafeFileWriter::new(file);
-        Ok(Box::new(writer))
+        Ok(BufWriter::new(Box::new(writer)))
     }
 
     fn delete(&self, path: &Path) -> result::Result<(), FileError> {
diff --git a/src/directory/mod.rs b/src/directory/mod.rs
index 6716d0193..d6873ecc8 100644
--- a/src/directory/mod.rs
+++ b/src/directory/mod.rs
@@ -7,8 +7,9 @@ mod shared_vec_slice;
 /// Errors specific to the directory module.
 pub mod error;
 
-use std::io::{Seek, Write};
+use std::io::{Write, Seek};
 
+use std::io::BufWriter;
 pub use self::read_only_source::ReadOnlySource;
 pub use self::directory::Directory;
 pub use self::ram_directory::RAMDirectory;
@@ -22,14 +23,14 @@ impl<T: Seek + Write> SeekableWrite for T {}
 ///
 /// `WritePtr` are required to implement both Write
 /// and Seek.
-pub type WritePtr = Box<SeekableWrite>;
+pub type WritePtr = BufWriter<Box<SeekableWrite>>;
 
 #[cfg(test)]
 mod tests {
 
     use super::*;
-    use std::path::Path;
-    use std::io::SeekFrom;
+    use std::path::Path;   
+    use std::io::{Write, Seek, SeekFrom};
 
     lazy_static! {
         static ref TEST_PATH: &'static Path = Path::new("some_path_for_test");
diff --git a/src/directory/ram_directory.rs b/src/directory/ram_directory.rs
index 30e131237..6ced0ae7e 100644
--- a/src/directory/ram_directory.rs
+++ b/src/directory/ram_directory.rs
@@ -1,7 +1,6 @@
 use std::collections::HashMap;
 use std::fmt;
-use std::io;
-use std::io::{Cursor, Write, Seek, SeekFrom};
+use std::io::{self, BufWriter, Cursor, Write, Seek, SeekFrom};
 use std::path::{Path, PathBuf};
 use std::result;
 use std::sync::{Arc, RwLock};
@@ -173,7 +172,7 @@ impl Directory for RAMDirectory {
             Err(OpenWriteError::FileAlreadyExists(path_buf))
         }
         else {
-            Ok(Box::new(vec_writer))
+            Ok(BufWriter::new(Box::new(vec_writer)))
         }
     }
 
diff --git a/src/fastfield/serializer.rs b/src/fastfield/serializer.rs
index 7c71661d7..f9af432b3 100644
--- a/src/fastfield/serializer.rs
+++ b/src/fastfield/serializer.rs
@@ -1,8 +1,7 @@
 use common::BinarySerializable;
 use directory::WritePtr;
 use schema::Field;
-use std::io;
-use std::io::{SeekFrom, Write};
+use std::io::{self, SeekFrom, Seek, Write};
 use super::compute_num_bits;
 
 
diff --git a/src/postings/serializer.rs b/src/postings/serializer.rs
index f1724ad46..5fb7c9505 100644
--- a/src/postings/serializer.rs
+++ b/src/postings/serializer.rs
@@ -13,6 +13,7 @@ use DocId;
 use core::Segment;
 use std::io;
 use core::SegmentComponent;
+use std::io::Write;
 use common::VInt;
 use common::BinarySerializable;