static Schema getSchema(Class<? extends Message> clazz) {
    return getSchema(ProtobufUtil.getDescriptorForClass(clazz));
  }
@Test
  public void testOptionalNestedSchema() {
    assertEquals(
        TestProtoSchemas.OPTIONAL_NESTED_SCHEMA,
        ProtoSchemaTranslator.getSchema(Proto2SchemaMessages.OptionalNested.class));
  }