public void AddCustomData_WhenCustomDataIsEmpty_AddsTheCustomData()
        {
            // Arrange
            var key   = "Identifier";
            var value = "value";

            // Act
            _uut.AddCustomData(key, value);

            // Assert
            Assert.Multiple(() =>
            {
                Assert.That(_uut.CustomData, Contains.Key(key));
                Assert.That(_uut.CustomData, Contains.Value(value));
            });
        }