for
Answer an AvailTask suitable for resuming the specified fiber using the specified action. If the continuation fails for any reason, then it aborts the fiber and invokes the failure continuation with the terminal throwable.
Return
An action that sets the execution state of the fiber to running, binds it to the running thread's interpreter, and then runs the specified continuation.
Parameters
fiber
A fiber.
body
What to do to resume execution of the fiber.