code: public static SpanContext create(
        TraceId traceId, SpanId spanId, TraceOptions traceOptions, Tracestate tracestate) {
      return new SpanContext(traceId, spanId, traceOptions, tracestate);
    }
docs: Creates a new {@code SpanContext} with the given identifiers and options.
  
  @param traceId the trace identifier of the span context.
  @param spanId the span identifier of the span context.
  @param traceOptions the trace options for the span context.
  @param tracestate the trace state for the span context.
  @return a new {@code SpanContext} with the given identifiers and options.
  @since 0.16