func TestManagerWithoutTransports(t *testing.T) {
	assert := assert.New(t)

	var (
		c   = Config{}
		tr  transports.Transport
		err error
	)

	tr, err = c.Open()
	if assert.NoError(err) && assert.NotNil(tr) {

		err = tr.Close()
		assert.NoError(err)
	}
}
func TestManagerWithOneTransport(t *testing.T) {
	assert := assert.New(t)

	var (
		c   = Config{udp.Config{}}
		tr  transports.Transport
		err error
	)

	tr, err = c.Open()
	if assert.NoError(err) && assert.NotNil(tr) {
		t.Logf("addrs=%v", tr.Addrs())

		err = tr.Close()
		assert.NoError(err)
	}
}