Macro impl_dynamic_send

Source
macro_rules! impl_dynamic_send {
    (Send; $($ty:ty),+) => { ... };
    (Send; builtin::{$($ty:ident),+}) => { ... };
    (tuple; $($arg:ident: $ty:ident),*) => { ... };
    (!Send; $($ty:ident),+) => { ... };
}
Available on since_api="4.2" only.