cancel should be done with an outbound user event

[weissi]

async-http-client/Sources/AsyncHTTPClient/HTTPHandler.swift

Lines 398 to 402 in e9d0dd2

	self.lock.withLock {
	if !cancelled {
	cancelled = true
	channel?.pipeline.fireUserInboundEventTriggered(TaskCancelEvent())
	}

the above code would be better done with an outbound user event, so something like

channel.triggerOutboundUserEvent(CancelEvent)

as an added benefit, that returns a promise so we can know if that was successful or not. The promise will be failed automatically if that has been handled before or the channel is already closed.

[weissi]

something like

if let channel = channel {
    try channel.triggerUserOutboundEvent(TaskCancelEvent()).wait()
} else {
    // failed, do we need to tell anybody?
}

should work much better because we actually get feedback from the channel.

Generally, all inbound events are for things that have happened (that you now need to handle). All outbound events are for operations that you want to happen.

[weissi]

@artemredkin this won't break public API, correct?

[weissi]

I'm assigning it to the 1.0.0 milestone for now in case it does so we don't forget it. If we're 100% sure it doesn't break API, this can be moved to the 1.1.0 milestone.