stage: moving performance enhancements into main

several incomplete features are gated behind the `experimental_features` flag.

src/common/bit_source_builder.rs

@@ -18,6 +18,8 @@
 
 // import java.io.ByteArrayOutputStream;
 
+use std::io::Write;
+
 /**
  * Class that lets one easily build an array of bytes by appending bits at a time.
  *
@@ -71,3 +73,19 @@ impl Default for BitSourceBuilder {
         Self::new()
     }
 }
+
+impl Write for BitSourceBuilder {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        let mut written = 0;
+        for byte in buf.iter() {
+            self.write(*byte as u32, 8);
+            written += 1;
+        }
+
+        Ok(written)
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}