Implement SendWriter for METADAPT-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
+	// SendWriter sends data written to an [io.Writer]. The writer must be
-	// previously opened through this function will be discarded. This
+	// closed after use. Closing the writer flushes any data that hasn't
-	// method is not safe for concurrent use, and neither is its result.
+	// been written yet. Any writer previously opened through this function
-	SendWriter(method uint16) (io.Writer, error)
+	// 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)

metadapta.go

@@ -9,7 +9,7 @@ import "git.tebibyte.media/sashakoshka/go-util/sync"
 
 const closeMethod = 0xFFFF
 const int64Max = int64((^uint64(0)) >> 1)
-
+const defaultChunkSize = 0x1000
 
 // Party represents a side of a connection.
 type Party bool; const (
@@ -171,6 +171,8 @@ type transA struct {
 	id            int64
 	incoming      usync.Gate[incomingMessage]
 	currentReader io.Reader
+	currentWriter io.Closer
+	writeBuffer   []byte
 }
 
 func (this *transA) Close() error {