DoInSpan does `f` function inside span using tracer in the context.

GetSpan returns current span or noopSpan if no span was created.

NewTracer creates new instance of Tracer with given exporter builder.

NewWriterExporter returns the writer exporter for spans.

StartSpan creates spans using tracer in the context.

TraceIDRatioBasedSampler samples a given fraction of traces.

WithExporter sets additional exporter builders for spans.

WithSampler sets sampler, by default there is no sampler.

WithServiceName sets service name that will be in attributes of all spans created by this tracer in "service.name" key.

Tracer is the root tracing entity that can enables creation of spans, and its export to the desired backends in a form of traces.

Span is the individual component of a trace.

Option sets the value of an option for a Config.

TracerStartSpanOption sets the value in tracerStartSpanOptions.