Describe the bug, including details regarding any error messages, version, and platform.

I am working with an internal tool that establishes a flightsql gRPC connection to a thing. The tool sets DriverConfig.TLSEnabled to false but I still see this error when the connection is being created:

grpc: the credentials require transport level security (use grpc.WithTransportCredentials() to set)

This error is coming from grpc-go's ClientConn.validateTransportCredential but only after calling the RequireTransportSecurity() method of the PerRPCCredentials trait.

The flightsql driver's grpcCredentials type implements this interface, but it doesn't seem to have any way to respect the aforementioned DriverConfig.TLSEnabled field.

I am about to open a PR to propose threading the config parameter through and have flightsql's grpcCredentials.RequireTransportSecurity() implementation respect it (definitely open to alternative approaches). I am writing up this issue because the CONTRIBUTING doc suggested I do so before opening a PR.

Component(s)

FlightRPC, Go