Refactor RDP proxy handling and update related tests

agents/rap-node-agent/internal/fabricproto/session_frames_test.go

@@ -1,6 +1,7 @@
 package fabricproto
 
 import (
+	"bytes"
 	"errors"
 	"testing"
 )
@@ -36,6 +37,9 @@ func TestHandleFrameOpensStreamAndReceivesData(t *testing.T) {
 	if len(responses) != 1 || responses[0].Type != FrameAck || responses[0].StreamID != 7 || responses[0].Sequence != 11 {
 		t.Fatalf("responses = %+v, want ack for stream 7 seq 11", responses)
 	}
+	if !bytes.Equal(responses[0].Payload, DataAckPayload([]byte("rdp-input"))) {
+		t.Fatalf("ack checksum = %x, want sha256 payload checksum", responses[0].Payload)
+	}
 	snapshot := session.Snapshot()
 	if snapshot.FramesReceived != 1 || snapshot.Streams[7].Received != 1 {
 		t.Fatalf("received metrics = %+v stream=%+v", snapshot, snapshot.Streams[7])