Check whether a future is resolved or not
resolved(x, ...)A Future, a list, or an environment (which also includes list environment.
Not used.
A logical of the same length and dimensions as x.
Each element is TRUE unless the corresponding element is a
non-resolved future in case it is FALSE.
This method needs to be implemented by the class that implement
the Future API. The implementation must never throw an error,
but only return either TRUE or FALSE.
It should also be possible to use the method for polling the
future until it is resolved (without having to wait infinitely long),
e.g. while (!resolved(future)) Sys.sleep(5).