dynamic computation()
)
Creates a future containing the result of calling computation
asynchronously with scheduleMicrotask.
If executing computation
throws,
the returned future is completed with the thrown error.
If calling computation
returns a Future, completion of
the created future will wait until the returned future completes,
and will then complete with the same result.
If calling computation
returns a non-future value,
the returned future is completed with that value.