Macro write_or 

macro_rules! write_or {
    ($dst:expr, $($arg:tt)*) => { ... };
}

Just like the std lib write! macro except that it suppresses in fmt::Result.

This should only be used if you are in control of the buffer you’re writing to and the only way it can fail is if the OS allocator fails.

• See: https://doc.rust-lang.org/std/io/trait.Write.html#method.write_fmt