I am Joe Tsai and the reason why my bzip2 encoder implementation has not been merged is because I have not had time to do it. Though I am a contributor to the standard library, curating and improving it is not my primary responsibility. In contrast, my other responsibilities have continually kept any intention to merge the bzip2 encoder implementation at the bottom of the task list. The most complicated portion of a bzip2 encoder is the implementation for a
suffix array construction algorithm (SACA). Such algorithms are fairly complex and require quite an investment by the reviewer to understand. Given that its' been years since I touched the code, I would hardly consider myself well-versed in SACAs at this point in time.