Hi Joshua,

This is indeed a problem -- I just never expected that you would be having that many events and and canceling the majority.  I am sorry you had to debug this. :-(

This was anticipated by the author of pyftpdlib (Giampaolo Roloda'), who proposed an elegant solution: keep track of the number of cancelled events, and when the number gets too high (according to some measure) the heapq is simply rebuilt by filtering out cancelled events.  I think this is similar to your proposal (b).

I would love it if you could implement this!  Just make sure to add some tests and follow the PEP 8 style guide.  You can contribute upstream to the Tulip project first.  https://code.google.com/p/tulip/