code: public void emitAnnotation(@Nonnull ZipkinData zipkinData, @Nonnull String s) {
          long timestampMillis = clock.millis();
          long timestampMicros = TimeUnit.MILLISECONDS.toMicros(timestampMillis);
  
          ZipkinAnnotationsStore store = prepareEmission(zipkinData, s).addAnnotation(timestampMicros, s);
          emitAnnotations(store);
      }
docs: Emits a single annotation to Zipkin.
  
  @param zipkinData Zipkin request data
  @param s          The annotation to emit