execute requests (default: 16).
  * **rpc_timeout** (*float**, **optional*) -- The default
    timeout, in seconds, for RPC requests (default: 60 seconds).
    If the RPC has not completed in this timeframe, an exception
    indicating so will be raised. Callers can override this
    timeout for individual RPCs in "rpc_sync()" and "rpc_async()"
    if necessary.

  * **init_method** (*str**, **optional*) -- The URL to initialize
    the distributed store used for rendezvous. It takes any value
    accepted for the same argument of "init_process_group()"
    (default: "env://").

  * **device_maps** (*Dict**[**str**, **Dict**]**, **optional*) --
    Device placement mappings from this worker to the callee. Key
    is the callee worker name and value the dictionary ("Dict" of
    "int", "str", or "torch.device") that maps this worker's
    devices to the callee worker's devices. (default: "None")
