code: public static void putSpanContextAttachments(MeasureMap measureMap, SpanContext spanContext) {
      checkNotNull(measureMap, "measureMap");
      checkNotNull(spanContext, "spanContext");
      measureMap.putAttachment(
          ATTACHMENT_KEY_SPAN_CONTEXT, AttachmentValueSpanContext.create(spanContext));
    }
docs: Puts a {@link SpanContext} into the attachments of the given {@link MeasureMap}.
  
  @param measureMap the {@code MeasureMap}.
  @param spanContext the {@code SpanContext} to be put as attachments.
  @since 0.16