OtelGettingStartedElixir

Assuming the 3 env vars are set as per the erlang getting started repo:

export OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://api.honeycomb.io:443
export OTEL_EXPORTER_OTLP_PROTOCOL=grpc
export OTEL_EXPORTER_OTLP_TRACES_HEADERS=x-honeycomb-team=<HONEYCOMB_API_TOKEN>,x-honeycomb-dataset=experiments

Running iex -S mix prints out the warning:

[warn]  OTLP tracer, :opentelemetry_exporter, failed to initialize when using GRPC protocol. Verify you have the `grpcbox` dependency included.

Other notes:

• As far as I can see it's a error:badarg being thrown by ExporterModule:init(Config) in opentelemetry that causes the issue, however digging into that part of the opentelemetry_exporter package I can't seem to see a difference between the parameters passed to grpc_channel:start_link when running the erlang version vs. the elixir one
• Setting OTEL_EXPORTER_OTLP_PROTOCOL to grpc doesn't seem to do anything - I've had to set it in config/runtime.exs to get picked up
• I've set all 3 dependencies to work from 1.0.0-rc.1 (when testing with the erlang project I've done the same)
• [Minor] The config passed to opentelemetry_exporter when it's being set to the exporter for otel_batch_processor needs to be a map (%{}), not a list (however the console exporter from the getting started guide uses a list)