src/libs/Bus.js
function _removeSubscribers(aSubscribers, oSubscriber) {
  let nUnsubscribed = 0;
  if (!isTypeOf(aSubscribers, sNotDefined)) {
    let nIndex = aSubscribers.length - 1;
    for (; nIndex >= 0; nIndex--) {
      if (aSubscribers[nIndex].subscriber === oSubscriber) {
        nUnsubscribed++;
        aSubscribers.splice(nIndex, 1);
      }
    }
  }
  return nUnsubscribed;
}
function _removeSubscribers(aSubscribers, oSubscriber) {
  let nUnsubscribed = 0;
  if (!isTypeOf(aSubscribers, sNotDefined)) {
    let nIndex = aSubscribers.length - 1;
    for (; nIndex >= 0; nIndex--) {
      if (aSubscribers[nIndex].subscriber === oSubscriber) {
        nUnsubscribed++;
        aSubscribers.splice(nIndex, 1);
      }
    }
  }
  return nUnsubscribed;
}
_removeSubscribers remove the subscribers to one channel and return the number of
subscribers that have been unsubscribed.
@param {Array<Object>} aSubscribers
@param {Object} oSubscriber
@return {Number}
@private