def to_s(infoHash = nil)
      def makeFlags(peer)
        s = "["
        s << "c" if peer.amChoked
        s << "i" if peer.peerInterested
        s << "C" if peer.peerChoked
        s << "I" if peer.amInterested
        s << "]"
        s
      end    

      if infoHash
        s = "Peers: \n"
        peers = @peersByInfoHash[infoHash]
        if peers
          peers.each do |peer|
            s << "  #{peer.to_s} #{makeFlags(peer)}\n"
          end
        end
      else
        "PeerHolder"
      end
      s 
    end
def to_s(infoHash = nil)
      def makeFlags(peer)
        s = "["
        s << "c" if peer.amChoked
        s << "i" if peer.peerInterested
        s << "C" if peer.peerChoked
        s << "I" if peer.amInterested
        s << "]"
        s
      end    

      if infoHash
        s = "Peers: \n"
        peers = @peersByInfoHash[infoHash]
        if peers
          peers.each do |peer|
            s << "  #{peer.to_s} #{makeFlags(peer)}\n"
          end
        end
      else
        "PeerHolder"
      end
      s 
    end
Output a string representation of the PeerHolder, for debugging purposes.