function push( b ) {
	/* eslint-disable no-invalid-this */
	var self = this;

	this._benchmarks.push( b );

	b.once( 'prerun', onPreRun );
	b.on( 'result', onResult );

	this.emit( '_push', b );

	/**
	* Callback invoked upon a `prerun` event.
	*
	* @private
	*/
	function onPreRun() {
		self._stream.write( '# '+b.name+'\n' );
	}

	/**
	* Callback invoked upon a `result` event.
	*
	* @private
	* @param {(Object|string)} res - result
	* @returns {void}
	*/
	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 );
	}
}
Adds a new benchmark.

@private
@param {Benchmark} b - benchmark