A frozen pre-#847 copy of DriverHealth (test-only telemetry_pre847.proto, generated via
Grpc.Tools in the test project) stands in for an old node / old central: new->new round-trips
the node id; old->new parses as absent (HasReportingNodeId false -> null, not "") with every
other field intact; new->old ignores field 15 without shifting known fields and preserves it as
an unknown field.
Joseph Doherty