I am the current maintainer of the spellcheck GitHub action I am sunsetting version 0.24.0 as by the proposed sunset policy. This version is mentioned in your code, but it has been commented out.
Please let me know if you need assistance with the action and I will see if I can help.
Currently Future is an all in one that allows interrogating results and fulfilling the future as well. This disallows restricting fulfillment by consumers.
Refactoring Future into a protocol that only allows interrogation and a sub-protocol, FulfillableFuture, that adds fulfillment capabilities would allow choosing which capabilities to expose to consumers.
The current Future implementation would need to be renamed (e.g. AsyncFuture or StdFuture) and would simply implement both protocols.