Distributed method is always `async throws` outside of its isolation
context, so accessor has to be `async throws` as well, and be able
to forward error value from the call to the outside.
Accessor infers result(s) from the underlying distributed method its
going to call, and forwards all of the results produced by such call
up to the caller.
`DistributedAccessor::computeArguments` handles loading of the argument
values from the provided `UnsafeRawPointer` (managed by the caller),
coercing retrieved arguments to appropriate platform-native representation,
and exploding object to form correct argument sequence for distributed
method call.
