For doing application-level writes to the standard error stream. Coordinates also with debug-level writes that are ignorant of Io interface and implementations.
See also:
tryLockStderrpub fn lockStderr(io: Io, buffer: []u8, terminal_mode: ?Terminal.Mode) Cancelable!LockedStderr
pub fn lockStderr(io: Io, buffer: []u8, terminal_mode: ?Terminal.Mode) Cancelable!LockedStderr {
const ls = try io.vtable.lockStderr(io.userdata, terminal_mode);
try ls.clear(buffer);
return ls;
}