This can be utilized by using already existing [`mergeRetryOptions`](https://github.com/googleapis/gax-nodejs/blob/3c3c689266e6ff2446408daffa9d3848d72bcb57/src/gax.ts#L510) function while [merging](https://github.com/googleapis/gax-nodejs/blob/3c3c689266e6ff2446408daffa9d3848d72bcb57/src/gax.ts#L218) settings with user provided callOptions during [createApiCall](https://github.com/googleapis/gax-nodejs/blob/3c3c689266e6ff2446408daffa9d3848d72bcb57/src/createApiCall.ts#L72)