I'm realizing there's 3 ways to do this in the exporters:

1. Have HTTP AND GRPC specific env vars for metrics/logs/traces.
2. Just one set of env vars for metrics/logs/traces that encompasses HTTP / GRPC, and we pass "HTTP" or "GRPC" to the entry point as an argument...
3. Just one set of env vars, and the entry point provider has 2 entry points (one for HTTP one for GRPC), and the user must set the right entry point name in the env var depending on if they want HTTP or GRPC..

I'm going forward with #2 since that's simplest for both the user and the entry point provider. So the function signature that gets associated w/ the entry point should look like:

def credential_provider(otlp_exporter_type: Literal["HTTP", "GRPC"]) -> Union[requests.Session, grpc.ChannelCredentials]