refactor: encapsulate fiber::csw utility functions
Follow-up for !251 (merged) (an alternative layout)
This patch provides new public items:
tarantool::fiber::csw()
tarantool::fiber::check_yield()
tarantool::fiber::YieldResult
- Move the code into another module -
tarantool::fiber::csw
. - The module itself is private, but it's content is re-exported in
tarantool::fiber
module. - Make them accessible without
tarantool_test
feature flag. - Rename YieldResult in the past tense: Yielded / DidntYield.
- Supply it with the documentation.
Edited by Yaroslav Dynnikov