- SizeEstimator was following through a ClassLoader field of Hadoop
  JobConfs, which referenced the whole interpreter, Scala compiler, etc.
  Chaos ensued, giving an estimated size in the tens of gigabytes.
- Broadcast variables in local mode were only stored as MEMORY_ONLY and
  never made accessible over a server, so they fell out of the cache when
  they were deemed too large and couldn't be reloaded.