code: function isChannelTag (tagName, prefix, local, feedType) {
    return tagName === 'channel' || tagName === 'feed'
      || (local === 'channel' && (prefix === '' || feedType === 'rdf'))
      || (local === 'feed' && (prefix === '' || feedType === 'atom'))
  }
docs: Determines whether or not the current tag is a channel/feed
  
  @param tagName
  @param prefix
  @param local
  @param feedType
  @returns {boolean}