* Pool class no longer uses recursion when a request is intercepted. * The size of a Pool can now be dynamically adjusted using a callback. See https://github.com/guzzle/guzzle/pull/943. * Setting a request option to `null` when creating a request with a client will ensure that the option is not set. This allows you to overwrite default request options on a per-request basis. See https://github.com/guzzle/guzzle/pull/937. * Added the ability to limit which protocols are allowed for redirects by specifying a `protocols` array in the `allow_redirects` request option. * Nested futures due to retries are now resolved when waiting for synchronous responses. See https://github.com/guzzle/guzzle/pull/947. * `"0"` is now an allowed URI path. See https://github.com/guzzle/guzzle/pull/935. * `Query` no longer typehints on the `$query` argument in the constructor, allowing for strings and arrays. * Exceptions thrown in the `end` event are now correctly wrapped with Guzzle specific exceptions if necessary.