fill_buffer do something only if buf is empty

src/stream.rs

@@ -101,14 +101,16 @@ impl ByteStreamReader {
 		}
 	}
 
-	/// Tries to fill the internal read buffer from the underlying stream.
+	/// Tries to fill the internal read buffer from the underlying stream if it is empty.
 	/// Calling this might be necessary to ensure that `.eos()` returns a correct
 	/// result, otherwise the reader might not be aware that the underlying
 	/// stream has nothing left to return.
 	pub async fn fill_buffer(&mut self) {
+		if self.buf.is_empty() {
 			let packet = self.stream.next().await;
 			self.add_stream_next(packet);
 		}
+	}
 
 	/// Clears the internal read buffer and returns its content
 	pub fn take_buffer(&mut self) -> Bytes {