Puts a fixed-sized integer into the stream. This method is needed because numbers are usually written in a compressed form (for example, ``1'' takes one byte, and ``512'' takes up two bytes, regardless of the C++ type that the number had).
In many cases it is useful to temporary write a 0 to a stream, write more data, and then go back and change the 0 to another number; this requires a fixed-size number.
Data written to a stream with PutFixed must be read with
wxMediaStreamIn::GettFixed (section 
).