Trying to insert spans with end_time < start_time

[jgpruitt]

I'm seeing this error in the promscale logs in the opentelemetry-demo. I'm not sure if the opentelemetry collector is sending spans this way, or if we're doing something to accidentally put the start_time after the end_time. We should probably do something with these violations in the Go code rather than rely on the database to catch them.

opentelemetry-demo-promscale-1  | level=error ts=2022-01-28T16:50:35.941Z caller=runner.go:50 msg="error in GRPC call" err="error sending trace batches: ERROR: new row for relation \"_hyper_1_5_chunk\" violates check constraint \"span_check\" (SQLSTATE 23514)"

[jgpruitt]

Postgres timestamptz has microsecond resolution while the Span struct in Go is using nanosecond resolution