macro_rules! fwd { ([ $fwd:expr ], $arg:expr) => { ... }; ([ $fwd:expr ] $(, $arg:expr)*) => { ... }; }
Forward data via a Fwd instance
Fwd
fwd!([fwd2zz], arg1, arg2...);
There may be zero or more arguments, and they must match the message type. Implemented using Fwd::fwd
Fwd::fwd