0.19

• This release is published to Maven Central.
• DefaultDispatcher is introduced (see #136):
  • launch, async, produce, actor and other integration-specific coroutine builders now use
    DefaultDispatcher as the default value for their context parameter.
  • When a context is explicitly specified, newCoroutineContext function checks if there is any
    interceptor/dispatcher defined in the context and uses DefaultDispatcher if there is none.
  • DefaultDispatcher is currently defined to be equal to CommonPool.
  • Examples in the guide now start with launch { ... } code and explanation on the nature
    and the need for coroutine context starts in "Coroutine context and dispatchers" section.
• Parent coroutines now wait for their children (see #125):
  • Job completing state is introduced in documentation as a state in which parent coroutine waits for its children.
  • Job.attachChild and Job.cancelChildren are introduced.
  • Job.join now always checks cancellation status of invoker coroutine for predictable behavior when joining
    failed child coroutine.
  • Job.cancelAndJoin extension is introduced.
  • CoroutineContext.cancel and CoroutineContext.cancelChildren extensions are introduced for convenience.
  • withTimeout/withTimeoutOrNull blocks become proper coroutines that have CoroutineScope and wait for children, too.
  • Diagnostics in cancellation and unexpected exception messages are improved,
    coroutine name is included in debug mode.
  • Fixed cancellable suspending functions to throw CancellationException (as was documented before) even when
    the coroutine is cancelled with another application-specific exception.
  • JobCancellationException is introduced as a specific subclass of CancellationException which is
    used for coroutines that are cancelled without cause and to wrap application-specific exceptions.
  • Job.getCompletionException is renamed to Job.getCancellationException and return a wrapper exception if needed.
  • Introduced Deferred.getCompletionExceptionOrNull to get not-wrapped exception result of async task.
  • Updated docs for Job & Deferred to explain parent/child relations.
• select expression is modularized:
  • SelectClause(0,1,2) interfaces are introduced, so that synchronization
    constructs can define their select clauses without having to modify
    the source of the SelectBuilder in kotlinx-corounes-core module.
  • Job.onJoin, Deferred.onAwait, Mutex.onLock, SendChannel.onSend, ReceiveChannel.onReceive, etc
    that were functions before are now properties returning the corresponding select clauses. Old functions
    are left in bytecode for backwards compatibility on use-site, but any outside code that was implementing those
    interfaces by itself must be updated.
  • This opens road to moving channels into a separate module in future updates.
• Renamed TimeoutException to TimeoutCancellationException (old name is deprecated).
• Fixed various minor problems:
  • JavaFx toolkit is now initialized by JavaFx context (see #108).
  • Fixed lost ACC_STATIC on methods (see #116).
  • Fixed link to source code from documentation (see #129).
  • Fixed delay in arbitrary contexts (see #133).
• kotlinx-coroutines-io module is introduced. It is a work-in-progress on ByteReadChannel and ByteWriteChannel
  interfaces, their implementations, and related classes to enable convenient coroutine integration with various
  asynchronous I/O libraries and sockets. It is currently unstable and will change in the next release.