OptionalattributesThe list of attributes returned by SamplingResult MUST be immutable. Caller may call Sampler.shouldSample any number of times and can safely cache the returned value.
A sampling decision, refer to SamplingDecision for details.
OptionaltraceA TraceState that will be associated with the Span through the new SpanContext. Samplers SHOULD return the TraceState from the passed-in Context if they do not intend to change it. Leaving the value undefined will also leave the TraceState unchanged.
A sampling result contains a decision for a Span and additional attributes the sampler would like to added to the Span.