def clients(jids, from, &filter)
      jids = filter_allowed(jids, from)
      local = @clients.values_at(*jids).compact.flatten.select(&filter)
      proxies = proxies(*jids).select(&filter)
      [local, proxies].flatten
    end
def clients(jids, from, &filter)
      jids = filter_allowed(jids, from)
      local = @clients.values_at(*jids).compact.flatten.select(&filter)
      proxies = proxies(*jids).select(&filter)
      [local, proxies].flatten
    end
Return the client streams to which the from address is allowed to
 contact. Apply the filter block to each stream to narrow the results
 before returning the streams.