When php develops the api interface

When the user requests the api, the server begins to perform logical operations. At this time, due to various reasons (for example: the other party's network is not good, the own server Network instability, cdn instability and other factors)

No return result. The API requested in this way will timeout and report an error (such as curl error28 Operation timed out after 3002 milliseconds with 0 bytes received).

The problem is that the API server has completed the data operation for this request (irreversible operation, if it is reversible, try cach). The requester cannot process its own logic without receiving the execution results.

Please give me some advice on development ideas.