Previously, the error stored in the async context was of type SwiftError
*. In order to enable the context to be callee released, make it
indirect and change its type to SwiftError **.
rdar://71378532
move comments to the wired up continuations
remove duplicated continuations; leep the wired up ones
before moving to C++ for queue impl
trying to next wait via channel_poll
submitting works; need to impl next()
Currently, the only thing in the system that donates a thread
to run it is swift_runAndBlockThread, but we'll probably need
others. Nothing in the concurrency runtime should block via a
semaphore in this configuration.
As an outrageous hack, work around the layering problems with
using libdispatch from the concurrency library on non-Darwin
systems by making those systems use the cooperative global
executor. This is only acceptable as a temporary solution
for landing this change and setting things onto the right
long-term design.
