Registers OpenTelemetryTracing for TracingMode.OpenTelemetry (TRACING_MODE=opentelemetry or otel).
Declared in this module's META-INF/services/org.llm4s.trace.spi.TracingBackend, so depending on llm4s-observability-otel is all it takes; Tracing.create finds it by ServiceLoader. That replaced the Class.forName reflection core used to load this module (#1133).
A class rather than an object because java.util.ServiceLoader instantiates it through a public no-arg constructor.
Builds the tracer from settings.openTelemetry. An SDK that cannot start is reported as an error here, rather than as a tracer whose every call fails. An unreachable collector is not such a failure: OTLP export is asynchronous, so it surfaces only in the exporter's own logs.
Builds the tracer from settings.openTelemetry. An SDK that cannot start is reported as an error here, rather than as a tracer whose every call fails. An unreachable collector is not such a failure: OTLP export is asynchronous, so it surfaces only in the exporter's own logs.