function-timer-function.php

<?php 
/**
 * Time a callable function/method
 * 
 * Returns an array containing the response of the callback in the first index,
 * and the total time for execution in the second key.
 *
 * @param  mixed  $callback  A callable function/method (i.e. `get_posts` or `array( $my_obj, 'my_method' )`)
 * @return mixed             Array with func value response, and execution time
 */
function wds_time_it( $callback ) {
	$args = func_get_args();
	// Remove callback from args
	unset( $args[ array_search( $callback, $args ) ] );

	if ( ! function_exists( 'microtime' ) ) {
		return array( call_user_func_array( $callback, $args ), false );
	}

	$time_start = microtime( true );

	$data_to_return = call_user_func_array( $callback, $args );

	$total_time = microtime( true ) - $time_start;

	return array( $data_to_return, $total_time );
}