polling endpoints should be available immediately after a 202

spec.md

@@ -274,6 +274,8 @@ If the query parameter described above is present, and the broker executes the r
 
 An asynchronous response triggers the platform marketplace to poll the endpoint `GET /v2/service_instances/:guid/last_operation` until the broker indicates that the requested operation has succeeded or failed. Brokers may include a status message with each response for the `last_operation` endpoint that provides visibility to end users as to the progress of the operation.
 
+Once a broker has returned the asynchronous response `202 ACCEPTED`, the `last_operation` endpoint should be ready to respond to polling requests immediately.
+
 #### Blocking Operations ####
 
 The marketplace must ensure that service brokers do not receive requests for an instance while an asynchronous operation is in progress. For example, if a broker is in the process of provisioning an instance asynchronously, the marketplace must not allow any update, bind, unbind, or deprovision requests to be made through the platform. A user who attempts to perform one of these actions while an operation is already in progress must receive an HTTP 400 response with the error message: `Another operation for this service instance is in progress`.