refactor how session tickets are sent

Previously, RunHandshake() would send the session tickets. Now, the
session initiates the sending of the session ticket. This simplifies the
setup a bit, and it will make it possible to include the RTT estimate in
the session ticket without accessing the RTTStats concurrently.

crypto_stream.go

@@ -22,35 +22,6 @@ type cryptoStream interface {
 	PopCryptoFrame(protocol.ByteCount) *wire.CryptoFrame
 }
 
-type postHandshakeCryptoStream struct {
-	cryptoStream
-
-	framer framer
-}
-
-func newPostHandshakeCryptoStream(framer framer) cryptoStream {
-	return &postHandshakeCryptoStream{
-		cryptoStream: newCryptoStream(),
-		framer:       framer,
-	}
-}
-
-// Write writes post-handshake messages.
-// For simplicity, post-handshake crypto messages are treated as control frames.
-// The framer functions as a stack (LIFO), so if there are multiple writes,
-// they will be returned in the opposite order.
-// This is acceptable, since post-handshake crypto messages are very rare.
-func (s *postHandshakeCryptoStream) Write(p []byte) (int, error) {
-	n, err := s.cryptoStream.Write(p)
-	if err != nil {
-		return n, err
-	}
-	for s.cryptoStream.HasData() {
-		s.framer.QueueControlFrame(s.PopCryptoFrame(protocol.MaxPostHandshakeCryptoFrameSize))
-	}
-	return n, nil
-}
-
 type cryptoStreamImpl struct {
 	queue  *frameSorter
 	msgBuf []byte