My objective is to use Guzzle 6 to create a pool of asynchronous requests that PUT json data. Then monitor each $promise success/failure.
For comparison to my POOL c
If you want full control, don't use the Request() object in your Pool. Instead, start the request yourself by having your pool's generator yielding a callable function which starts the request. That gives you total control of all options. Here is a correct code example:
https://stackoverflow.com/a/40622269/5562035