Macro fuchsia_trace::flow_begin

macro_rules! flow_begin {
    ($category:expr, $name:expr, $flow_id:expr $(, $key:expr => $val:expr)*) => { ... };
}

Convenience macro for the flow_begin function.

Example:

let flow_id = 1234;
flow_begin!("foo", "bar", flow_id, "x" => 5, "y" => "boo");

is equivalent to

flow_begin(cstr!("foo"), cstr!("bar"), flow_id,
    &[ArgValue::of("x", 5), ArgValue::of("y", "boo")]);