public void WriteOnce_SetsAndGets_ReturnsInstance()
{
WriteOnce <string> txt = new WriteOnce <string> {
Value = "Hello world"
};
Assert.True(txt.Value == "Hello world");
Assert.True(txt.ToString() == "Hello world");
Assert.True(txt.ValueOrDefault == "Hello world");
Assert.True((string)txt == "Hello world");
}