| MetricSet | Named numbers with their units, ready to be exported. |
| OtlpExporter | Posts spans and metrics to an OTLP endpoint. |
| OtlpPayload | Renders spans and metrics as OTLP over HTTP with a JSON body. |
| Span | One timed operation, in the shape OpenTelemetry transports. |
| TelemetryPass | Takes one reading of everything worth graphing, and exports it. |
| Tracer | Opens and closes spans, and holds them until something exports them. |