public MsgpackOutput use(MsgpackGenerator generator, Schema<?> schema)
    {
        this.schema = schema;
        this.generator = generator;
        return this;
    }
Before serializing a message/object tied to a schema, this should be called. This also resets the internal state
of this output.
protostuff-msgpack/src/main/java/io/protostuff/MsgpackOutput.java