@Nullable
  default Stub deserializeCustomStub(@NotNull StubInputStream stream) throws IOException {
    if (stream.readBoolean()) {
      final String typeName = stream.readNameString();
      for (StubType type : getExtensions()) {
        if (type.getClass().getCanonicalName().equals(typeName)) {
          return type.deserializeStub(stream);
        }
      }
      throw new IOException("Unknown custom stub type " + typeName);
    }

    return null;
  }
@Nullable
  default Stub deserializeCustomStub(@NotNull StubInputStream stream)