diff --git a/connection.go b/connection.go
index 05dec8a..7c82c8f 100644
--- a/connection.go
+++ b/connection.go
@@ -44,10 +44,12 @@ type Trans interface {
 		
 	// Send sends a message. This method is not safe for concurrent use.
 	Send(method uint16, data []byte) error
-	// SendWriter sends data written to an [io.Writer]. Any writer
-	// previously opened through this function will be discarded. This
-	// method is not safe for concurrent use, and neither is its result.
-	SendWriter(method uint16) (io.Writer, error)
+	// SendWriter sends data written to an [io.Writer]. The writer must be
+	// closed after use. Closing the writer flushes any data that hasn't
+	// been written yet. Any writer previously opened through this function
+	// will be discarded. This method is not safe for concurrent use, and
+	// neither is its result.
+	SendWriter(method uint16) (io.WriteCloser, error)
 	// Receive receives a message. This method is not safe for concurrent
 	// use.
 	Receive() (method uint16, data []byte, err error)