diff --git a/src/core/segment_reader.rs b/src/core/segment_reader.rs
index 208a73559..eb1d100d6 100644
--- a/src/core/segment_reader.rs
+++ b/src/core/segment_reader.rs
@@ -70,6 +70,10 @@ impl SegmentReader {
         self.segment_meta.num_docs()
     }
 
+    pub fn schema(&self) -> &Schema {
+        &self.schema
+    }
+
     /// Return the number of documents that have been
     /// deleted in the segment.
     pub fn num_deleted_docs(&self) -> DocId {
diff --git a/src/fastfield/reader.rs b/src/fastfield/reader.rs
index aa3050632..1d5dc35c6 100644
--- a/src/fastfield/reader.rs
+++ b/src/fastfield/reader.rs
@@ -244,3 +244,8 @@ impl FastFieldsReader {
                  })
     }
 }
+
+unsafe impl Send for U64FastFieldReader {}
+unsafe impl Sync for U64FastFieldReader {}
+unsafe impl Send for I64FastFieldReader {}
+unsafe impl Sync for I64FastFieldReader {}
\ No newline at end of file
diff --git a/src/indexer/index_writer.rs b/src/indexer/index_writer.rs
index 0a774a160..29417bcfb 100644
--- a/src/indexer/index_writer.rs
+++ b/src/indexer/index_writer.rs
@@ -346,6 +346,18 @@ impl IndexWriter {
         result
     }
 
+    #[doc(hidden)]
+    pub fn add_segment(&mut self, segment_meta: SegmentMeta) {
+        let delete_cursor = self.delete_queue.cursor();
+        let segment_entry = SegmentEntry::new(segment_meta, delete_cursor, None);
+        self.segment_updater.add_segment(self.generation, segment_entry);
+    }
+
+    #[doc(hidden)]
+    pub fn new_segment(&self) -> Segment {
+        self.segment_updater.new_segment()
+    }
+
     /// Spawns a new worker thread for indexing.
     /// The thread consumes documents from the pipeline.
     ///
diff --git a/src/lib.rs b/src/lib.rs
index 8588a0588..5029a6cf6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -90,22 +90,25 @@ pub type Result<T> = std::result::Result<T, Error>;
 
 mod core;
 mod compression;
-mod store;
 mod indexer;
-mod common;
+pub mod common;
 mod error;
 mod analyzer;
 mod datastruct;
 
-
-
 pub mod termdict;
 
+// Row-oriented, slow, compressed storage of documents
+pub mod store;
+
 /// Query module
 pub mod query;
+
 pub mod directory;
+
 /// Collector module
 pub mod collector;
+
 /// Postings module (also called inverted index)
 pub mod postings;
 /// Schema
@@ -123,6 +126,7 @@ pub use self::common::TimerTree;
 
 pub use postings::DocSet;
 pub use postings::Postings;
+pub use core::SegmentComponent;
 pub use postings::SegmentPostingsOption;