private void addPendingWrite(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
    PendingWriteQueue pendingWrites = this.pendingWrites;
    if (pendingWrites == null) {
        this.pendingWrites = pendingWrites = new PendingWriteQueue(ctx);
    }
    pendingWrites.add(msg, promise);
}
 

@Override
public void handlerAdded(final ChannelHandlerContext ctx) throws Exception {
    this.ctx = ctx;
    pendingUnencryptedWrites = new PendingWriteQueue(ctx);

    if (ctx.channel().isActive() && engine.getUseClientMode()) {
        // Begin the initial handshake.
        // channelActive() event has been fired already, which means this.channelActive() will
        // not be invoked. We have to initialize here instead.
        handshake(null);
    } else {
        // channelActive() event has not been fired yet.  this.channelOpen() will be invoked
        // and initialization will occur there.
    }
}