public Map<Integer, NetFlowV9FieldType> asMap() {
        return fieldTypes;
    }
@Test
    public void asMap() throws Exception {
        final NetFlowV9FieldTypeRegistry typeRegistry = NetFlowV9FieldTypeRegistry.create();
        final Map<Integer, NetFlowV9FieldType> map = typeRegistry.asMap();
        assertThat(map)
                .isNotEmpty()
                .containsEntry(1, NetFlowV9FieldType.create(1, NetFlowV9FieldType.ValueType.UINT32, "in_bytes"));
    }