* Replace `/bin/sleep` with just `sleep`, i.e. use environment variable
`$PATH` to locate binary.
* Replace `/usr/share/zoneinfo` with `$TZDIR` when it is defined,
fallback to hardcoded path otherwise. This is the same behavior that
Glibc2 normally have, see man 3 tzset.
* Fix#5128, #5184.
Removed flush() procedure from ioselectors.nim
Changed methods of work with application-driven data
* Make cache switch for kqueue, update test for it.
* Fix registerProcess bug returns wrong id.
Fix tupcoming_async test to compile with upcoming again.
Change socket() as unique identifier to dup(socket) as unique identifier.
