code: function parseHeaders(headers) {
    var parsed = {}, key, val, i;
  
    if (!headers) return parsed;
  
    forEach(headers.split('\n'), function(line) {
      i = line.indexOf(':');
      key = lowercase(trim(line.substr(0, i)));
      val = trim(line.substr(i + 1));
  
      if (key) {
        if (parsed[key]) {
          parsed[key] += ', ' + val;
        } else {
          parsed[key] = val;
        }
      }
    });
  
    return parsed;
  }
docs: Parse headers into key value object
  
  @param {string} headers Raw headers as a string
  @returns {Object} Parsed headers as key value object