TextMessageWriter
TextMessageWriter writes constraint descriptions and messages
in displayable form as a text stream. It tailors the display
of individual message components to form the standard message
format of NUnit assertion failure messages.
Prefix used for the actual value line of a message
Prefix used for the expected value line of a message
Length of a message prefix
public TextMessageWriter()
Construct a TextMessageWriter
Construct a TextMessageWriter, specifying a user message
and optional formatting arguments.