CloudFetch transport layer not configurable

[Multimo]

We are using the driver with large queries and when there is a large enough query that comes through, the driver swaps to cloudfetch.

Unfortunately the instance is behind a private network, smaller queries work but larger queries fail with a networkiong error: host is unavailable.

The httpClient the driver uses for most queries has a configurable transport however the httpClient that cloudfetch uses is not configurable unless you modify the global http.DefaultClient

We would like to ensure that all the drivers httpclients have a configurable transport layer that they all functionality can be used when a private network is involved.