Enhanced Error Classification in gRPC APIs

[a10zn8]

Is your feature request related to a problem? Please describe.
There exists a scenario in gRPC APIs where errors might still return with an 'OK' status code. This is especially true in situations where the API defines an extended error format. Currently, the ghz tool recognizes only 'non-OK' status as errors, which could lead to under-detection in the aforementioned cases.

It would be highly beneficial if ghz could incorporate a feature allowing manual error classification. This would provide users with a higher degree of control and accuracy in diagnosing and troubleshooting the performance of their gRPC APIs.

Describe the solution you'd like
Introduce a user-customizable function in ghz that analyses the response and decides if it's an error.