@Override public void flush(ChannelHandlerContext ctx) throws Exception { // Do not encrypt the first write request if this handler is // created with startTLS flag turned on. if (startTls && !sentFirstMessage) { sentFirstMessage = true; pendingUnencryptedWrites.removeAndWriteAll(); ctx.flush(); return; } if (pendingUnencryptedWrites.isEmpty()) { // It's important to NOT use a voidPromise here as the user // may want to add a ChannelFutureListener to the ChannelPromise later. // // See https://github.com/netty/netty/issues/3364 pendingUnencryptedWrites.add(Unpooled.EMPTY_BUFFER, ctx.newPromise()); } if (!handshakePromise.isDone()) { flushedBeforeHandshake = true; } wrap(ctx, false); ctx.flush(); }