add channel element; update channel interfaces

Signed-off-by: swpd <swpdtz@gmail.com>
finish channel support

Signed-off-by: swpd <swpdtz@gmail.com>
allow resume to any suspend coroutine

Signed-off-by: swpd <swpdtz@gmail.com>
update package interfaces

Signed-off-by: swpd <swpdtz@gmail.com>