More robust resolution/rejection of a promise

[trustin]

Motivation:

When a client does not receive a response or a server fails to process a
request within time limit, an invocation promise is rejected regardless
the final outcome of the invocation.

In such a case, a ServiceInvocationHandler or a remote invoker
implementation might attempt to resolve or reject the promise which is
already rejected with TimeoutException. Handling this sort of situations
is very common, and thus we should provide it as part of Armeria.

Modifications:

• Add ServiceInvocationContext.resolvePromise() and rejectPromise() to
  provide a simple and robust way to resolve or reject a promise in a
  ServiceInvocationHandler
• Use resolvePromise() and rejectPromise() wherever possible.
• Miscellaneous:
  • Fix a bug where WriteTimeoutException is raised rather than
    ResponseTimeoutException
  • Fix a bug where HttpSessionHandler.failPendingResponses() does not
    fail anything at all
  • Make TimeoutException traceless to reduce its instantiation overhead

Result:

• Robustness
  • Fixes potential issues when attempting to resolve a rejected promise.
  • Late responses are now silently discarded to avoid log message
    flooding

[trustin]

I wonder if we should make all timeout exceptions stacktraceless to avoid the overhead. Thoughts?

[He-Pin]

@trustin,if the stacktrace is not that useful but the message and the type mater,I think this would be great for the performance.

[trustin]

@hepin1989 Yep. Made the change in TimeoutException already.

[anuraaga]

I think timeouts should still be logged to info

[anuraaga]

Or maybe they're already logged in timeout handler? If so then it's ok, I guess it's very exceptional to even get to this code.

[trustin]

TimeoutException has already failed the promise. This if block is to swallow the result arrived after the timeout.

Armeria does not log any exceptions raised by a Service implementation. It uses the exceptions to produce proper error responses, and that's all. To log any exceptions raised by a Service, you'll have to decorate it. e.g. using LoggingService.

[trustin]

@anuraaga Thanks for merging :-)