code: func (km *keyMutex) LockKey(id string) {
  	glog.V(5).Infof("LockKey(...) called for id %q\r\n", id)
  	mutex := km.getOrCreateLock(id)
  	mutex.Lock()
  	glog.V(5).Infof("LockKey(...) for id %q completed.\r\n", id)
  }
docs: // Aquires a lock associated with the specified ID (creates the lock if one doesn't already exist).