Trace_context.Traceparent.of_value "xx":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-xxxx":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-0123456789abcdef0123456789abcdef":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-0123456789abcdef0123456789abcdef-xxxx":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-0123456789abcdef0123456789abcdef-xxxxxxxxxxxxxxxx":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-0123456789abcdef0123456789abcdef-0123456789abcdef":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-0123456789abcdef0123456789abcdef-0123456789abcdef-":
  Error "trace context must be 55 bytes"
Trace_context.Traceparent.of_value "00-0123456789abcdef0123456789abcdef-0123456789abcdef-00":
  Ok trace_id:"0123456789abcdef0123456789abcdef" parent_id:"0123456789abcdef"
Trace_context.Traceparent.of_value "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01":
  Ok trace_id:"4bf92f3577b34da6a3ce929d0e0e4736" parent_id:"00f067aa0ba902b7"
Trace_context.Traceparent.of_value "03-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01":
  Error "version is 3, expected 0"
Trace_context.Traceparent.of_value "00-ohnonohex7b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01":
  Error "in trace id: invalid hex char: 'o'"
Trace_context.Traceparent.of_value "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aazzzzzzb7-01":
  Error "in span id: invalid hex char: 'z'"

Trace_context.Traceparent.to_value trace_id:"4bf92f3577b34da6a3ce929d0e0e4736" parent_id:"00f067aa0ba902b7":
  "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-00"