Method constructor

lib/internal/http2/util.js:854–860

(integerCode, customErrorCode)

class NghttpError extends Error {
  constructor(integerCode, customErrorCode) {
    super(customErrorCode ?
      getMessage(customErrorCode, [], null) :
      binding.nghttp2ErrorString(integerCode));
    this.code = customErrorCode || 'ERR_HTTP2_ERROR';
    this.errno = integerCode;
  }

  get [kIsNodeError]() {
    return true;