Tells Cogl that you plan to replace all the buffer's contents. When this flag is used to map a buffer, the entire contents of the buffer become undefined, even if only a subregion of the buffer is mapped.
Tells Cogl that you plan to replace all the contents of the mapped region. The contents of the region specified are undefined after this flag is used to map a buffer.
Hints to Cogl about how you are planning to modify the data once it is mapped.