private void scheduleTimeout(final ChannelHandlerContext ctx, final ChannelPromise promise) {
// Schedule a timeout.
final WriteTimeoutTask task = new WriteTimeoutTask(ctx, promise);
task.scheduledFuture = ctx.executor().schedule(task, timeoutNanos, TimeUnit.NANOSECONDS);
if (!task.scheduledFuture.isDone()) {
addWriteTimeoutTask(task);
// Cancel the scheduled timeout if the flush promise is complete.
promise.addListener(task);
}
}
