function extractProtocol(address) {
  var match = protocolre.exec(address);

  return {
    protocol: match[1] ? match[1].toLowerCase() : '',
    slashes: !!match[2],
    rest: match[3]
  };
}
Extract protocol information from a URL with/without double slash ("//").

@param {String} address URL we want to extract from.
@return {ProtocolExtract} Extracted information.
@private