conservation of string parameters

[Kongaloosh]

The callback URL MAY contain arbitrary query string parameters (e.g., ?foo=bar&red=fish). Hubs MUST preserve the query string during subscription verification by appending new parameters to the end of the list using the & (ampersand) character to join. Existing parameters with names that overlap with those used by verification requests will not be overwritten. When sending the content distribution request, the hub will make a POST request to the callback URL including any query string parameters in the URL portion of the request, not as POST body parameters.