Remove unneeded forward declaration.
Canceling a task will not trigger the completion block with an NSError indicating the task was cancelled.
NSNull is now returned instead of @(YES) in places where a type of return or result is unexpected.
Simplified the FATask protocol and included some helper methods for attaching completion handlers to the task.
FAAbstractTask now exposes more of its synchronization mechanisms which are useful for subclasses.
Tried to simplify the interfaces for batch tasks (FAParallelTask & FAChainedTask) so see if it makes defining these types of tasks a bit easier.
FARetryTask now has a separate protocol that defines the retry configuration options instead of relying on blocks and properties.
FARetryTask now allows for setting the task factory through convenience initializers or setters to try to make creation of these tasks easier.