use it to compose a cache URL from the query body.

 *  New: Publish events when calls must wait to execute. `EventListener.dispatcherQueueStart()`
    is invoked when a call starts waiting, and `dispatcherQueueEnd()` is invoked when it's done.

 *  New: `Request.toCurl()` returns a copy-pasteable [curl] command consistent with Chrome’s and
    Firefox’s ‘copy as cURL’ features.