function onResult( res ) {
		// Check for a comment...
		if ( isString( res ) ) {
			return self._stream.write( '# '+res+'\n' );
		}
		if ( res.operator === 'result' ) {
			res = encodeResult( res );
			return self._stream.write( res );
		}
		self.total += 1;
		if ( res.ok ) {
			if ( res.skip ) {
				self.skip += 1;
			} else if ( res.todo ) {
				self.todo += 1;
			}
			self.pass += 1;
		}
		// According to the TAP spec, todos pass even if not "ok"...
		else if ( res.todo ) {
			self.pass += 1;
			self.todo += 1;
		}
		// Everything else is a failure...
		else {
			self.fail += 1;
		}
		res = encodeAssertion( res, self.total );
		self._stream.write( res );
	}
Callback invoked upon a `result` event.

@private
@param {(Object|string)} res - result
@returns {void}