public void writeHeaderPart(AnnotatedOutput out) {
    throwIfNotPrepared();

    int sz = protoIds.size();
    int offset = (sz == 0) ? 0 : getFileOffset();

    if (sz > 65536) {
      throw new UnsupportedOperationException("too many proto ids");
    }

    if (out.annotates()) {
      out.annotate(4, "proto_ids_size:  " + Hex.u4(sz));
      out.annotate(4, "proto_ids_off:   " + Hex.u4(offset));
    }

    out.writeInt(sz);
    out.writeInt(offset);
  }
Writes the portion of the file header that refers to this instance.

@param out {@code non-null;} where to write
android/android_framework/dex-maker/src/main/java/com/android/dx/dex/file/ProtoIdsSection.java