threshold
When a linear bin reaches this many entries and it's not already at the bottom allowable level (HashedSetBinDescriptor.numberOfLevels - 1) of the hash tree, then convert it to a hashed bin.
When a linear bin reaches this many entries and it's not already at the bottom allowable level (HashedSetBinDescriptor.numberOfLevels - 1) of the hash tree, then convert it to a hashed bin.