Added retry policy support for throttled requests. (Throttled requests receive a request rate too large exception, error code 429.) By default, DocumentClient retries nine times for each request when error code 429 is encountered, honoring the retryAfter time in the response header. A fixed retry interval time can now be set as part of the RetryOptions property on the ConnectionPolicy object if you want to ignore the retryAfter time returned by server between the retries. DocumentClient now waits for a maximum of 30 seconds for each request that is being throttled (irrespective of retry count) and returns the response with error code 429. This time can also be overriden in the RetryOptions property on ConnectionPolicy object.

DocumentClient now returns x-ms-throttle-retry-count and x-ms-throttle-retry-wait-time-ms as the response headers in every request to denote the throttle retry count and the cummulative time the request waited between the retries.

The RetryOptions class was added, exposing the RetryOptions property on the ConnectionPolicy class that can be used to override some of the default retry options.