Macro trace_println 

macro_rules! trace_println {
    () => { ... };
    ($s:expr) => { ... };
    ($s:expr, $($tt:tt)*) => { ... };
}

Macro for printing to the trace output, with a newline. Use the format! syntax to write data to the standard output. See std::fmt for more information.

Examples

trace_println!("Hello, World!");
trace_println!("format {} arguments", "some");