You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mt19937_64_test.go
    path of file: ./repos/gonum/mathext/prng
    
    the code of the file until where you have to start completion: // Copyright Â©2019 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package prng

im
    
func TestMT19937_64RoundTrip(t *testing.T) {
	t.Parallel()
	var src MT19937_64
	src.Seed(uint64(time.Now().Unix()))

	src.Uint64() // Step PRNG once to makes sure states are mixed.

	buf, err := src.MarshalBinary()
	if err != nil {
		t.Errorf("unexpected error marshaling state: %v", err)
	}

	var dst MT19937_64
	// Get dst into a non-zero state.
	dst.Seed(1)
	for i := 0; i < 10; i++ {
		dst.Uint64()
	}

	err = dst.UnmarshalBinary(buf)
	if err != nil {
		t.Errorf("unexpected error unmarshaling state: %v", err)
	}

	if dst != src {
		t.Errorf("mismatch between generator states: got:%+v want:%+v", dst, src)
	}
}