public SerializableFunction<Row, T> getFromRowFunction() {
    return fromRowFunction;
  }
@Test
  public void testMapRowToProto() {
    ProtoDynamicMessageSchema schemaProvider = schemaFromDescriptor(MapPrimitive.getDescriptor());
    SerializableFunction<Row, DynamicMessage> fromRow = schemaProvider.getFromRowFunction();
    MapPrimitive proto =
        parseFrom(fromRow.apply(MAP_PRIMITIVE_ROW).toString(), MapPrimitive.newBuilder()).build();
    assertEquals(MAP_PRIMITIVE_PROTO, proto);
  }