Carbon

This version brings a lot of internal refactoring and breaking changes + some new operators.

Now swift-async-algorithms has been anounced, this library can be seen as a companion for the Apple repo.
For now there is an overlap between both libraries, but when swift-async-algorithms becomes stable the overlapping operators while be deprecated in AsyncExtensions.

Nevertheless AsyncExtensions will continue to provide the operators that the community needs and are not provided by Apple.

• AsyncBufferedChannel/AsyncThrowingBufferedChannel: is the equivalent to AsyncChannel from Apple. The difference is that back-pressure is handled with a stack and the send operation is not suspending.
• Subjects: the subject suffix has been adopted to all the "hot" AsyncSequence with a shared output. A throwing counterpart has been added.
• zip and merge are top level functions to match Apple repo.
• AsyncThrowingJustSequence: an AsyncSequence that takes a throwing closure to compute the only element to emit.
• AsyncStream.pipe(): creates and AsyncStream by escaping the Continuation and returning a tuple to manipulate the inputs and outputs of the stream.
• mapToResult(): maps events (elements or failure) from an AsyncSequence to a Result. The resulting AsyncSequence cannot fail.
• AsyncLazySequence: is a renaming to match Apple repo for creating an AsyncSequence from a Sequence.