code: private void writeCompoundTagPayload(CompoundTag tag) throws IOException {
          for (Tag<?> childTag : tag.getValue().values()) {
              writeTag(childTag);
          }
          os.writeByte(TagType.TAG_END.getId()); // end tag - better way?
      }
docs: Writes a {@code TAG_Compound} tag.
  
  @param tag The tag.
  @throws java.io.IOException if an I/O error occurs.