lock helper.

[azjezz]

add AzJezz\Mutex\lock() helper functions.

stub :

function lock<T>((function(): T) $call): ?T;

usage example :

use function AzJezz\Mutex\lock;

function foo(): void {
  lock('foo-function', () ==> {
    // only one thread at a time may execute this statement
  });
}

this would require a new final abstract class MutexRepository to hold the mutex implementation to use with the lock helper.

stub :

final abstract class MutexRepository {
  public static function set(MutexInterface $mutex);

  /**
   * Implementation should throw an exception if the repository holds
   * no mutex implementations OR return a default implementation.
   *
   * if the implementation returned a default implementations, it should
   * call `set($default)` to ensure that the same instance is returned in the
   * next call.
   */
  public static function get(): MutexInterface;
}