Would be used for things like zip files, where the implementation mantains the contents in memory or on disk, and where the actual zip file isn't/shouldn't be written until one is finished filling it up (for zip due to inefficient file format).
See Implementation
Would be used for things like zip files, where the implementation mantains the contents in memory or on disk, and where the actual zip file isn't/shouldn't be written until one is finished filling it up (for zip due to inefficient file format).