Macro channel 

macro_rules! channel {
    (Send, $junction:ident, $name:ident, $type:ty) => { ... };
    (Recv, $junction:ident, $name:ident, $type:ty) => { ... };
    (Bidir, $junction:ident, $name:ident, $type:ty) => { ... };
}

An internal macro used by the junction macro.

The channel macro is used internally by the junction macro. For this reason it needs to be made available as part of the Public API of the Rusty Junctions crate.