Called by an application that wants to issue a request, without having it deeply queued by the browser
When the returned promise resolved, it is OK for the application to issue a request.
The promise resolves to an object that contains a done
method.
When the application's request has completed (or failed), the application must call the done
function
Identiy
will be called when request "slots" open up, allowing the caller to update priority or cancel the request Highest priority executes first, priority less than 0 cancels the request
a promise resolves to a object (with a done
field) when the request can be issued without queueing, resolves to null
if the request has been cancelled (by the callback return less than 0). In this case the application should not issue the request
Used to issue a request, without having them "deeply queued" by the browser.