code: function isValidTokenChar(ch) {
    if (ch >= 94 && ch <= 122)
      return true;
    if (ch >= 65 && ch <= 90)
      return true;
    if (ch === 45)
      return true;
    if (ch >= 48 && ch <= 57)
      return true;
    if (ch === 34 || ch === 40 || ch === 41 || ch === 44)
      return false;
    if (ch >= 33 && ch <= 46)
      return true;
    if (ch === 124 || ch === 126)
      return true;
    return false;
  }
docs: Verifies that the given val is a valid HTTP token
  per the rules defined in RFC 7230
  See https://tools.ietf.org/html/rfc7230#section-3.2.6
  
  Allowed characters in an HTTP token:
  ^_`a-z  94-122
  A-Z     65-90
  -       45
  0-9     48-57
  !       33
  #$%&'   35-39
  *+      42-43
  .       46
  |       124
  ~       126
  
  This implementation of checkIsHttpToken() loops over the string instead of
  using a regular expression since the former is up to 180% faster with v8 4.9
  depending on the string length (the shorter the string, the larger the
  performance difference)
  
  Additionally, checkIsHttpToken() is currently designed to be inlinable by v8,
  so take care when making changes to the implementation so that the source
  code size does not exceed v8's default max_inlined_source_size setting.
   /* istanbul ignore next