index.js
function setWritableHeader(res, name, value) {

  if (res._headerSent && res.finished) {
    return false;
  }

  res.setHeader(name, value);
  return true;
}
function setWritableHeader(res, name, value) {

  if (res._headerSent && res.finished) {
    return false;
  }

  res.setHeader(name, value);
  return true;
}
function setWritableHeader ( res , name , value ) { if ( res . _headerSent && res . finished ) { return false ; } res . setHeader ( name , value ) ; return true ; }
set writable header on response

@function setWritableHeader
@param {Object} res - response to client
@param {String} name - header's name
@param {String} value - header's value
@return {Boolean}
set writable header on response