Combat log events occur a lot more frequentrly than UNIT_HEALTH,
this library tracks incoming healing and damage and adjusts health values.
As a result you can see health updates sooner and more often.
This implementation is safe and accurate.
For each unit we keep history of health values after each change from combat log.
When UNIT_HEALTH arrives, UnitHealth value is searched in this log.
If it's found, then chain is valid, and library proceeds to return latest value from it.
If not it falls back onto UnitHealth value. If UnitHealth values in the next 1.4 seconds
also could not be found to re-validate combat log chain,
then it is reset with current UnitHealth value as a starting point.