tree ff36be420f997f6d9e50896f6db424048ff5c963
parent d0b5e379c7679313c75982214b0c32dd338634c2
author Rohan McGovern <rohan@mcgovern.id.au> 1675226669 +1000
committer Rohan McGovern <rohan@mcgovern.id.au> 1675227288 +1000

Reduce reference cycles to improve memory usage

Previously, a MapFuture and its delegate would always form a reference
cycle. If the futures point to large objects, this can result in
significant memory pressure as the cycle will not be freed until GC gets
around to it. Since GC is only triggered according to object counts and
not object sizes, this can increase apparent memory usage a lot in some
cases.

The cycle can be broken as soon as the delegate future has resolved, so
let's do that. (RetryFuture and PollFuture were already doing this, so
it seems there was an oversight specifically for MapFuture.)

Fixes #344