URI::MailTo#check_headers

# File tmp/rubies/ruby-3.0.5/lib/uri/mailto.rb, line 208
def check_headers(v)
  return true unless v
  return true if v.size == 0
  if HEADER_REGEXP !~ v
    raise InvalidComponentError,
      "bad component(expected opaque component): #{v}"
  end

  true
end