A sorted storage for Periods, intended to allocate a small
amount of memory; fast for small collections, but does not scale well
for insertions in large collections.
When the LazyTemporalAttributeStorage calls you back using this method
you have to:
1- load the entry when end instant is equal to instant, if any exists.
When the LazyTemporalAttributeStorage calls you back using this method
you have to:
1- Populate at least this storage with at least all the entries existing
intersecting the given period (=range), by calling the method
LazyTemporalAttributeStorage.putInCache(Period, Object)
It does not matter if you reload already loaded records, provided that they
are identical.
Maintains internally a TreeMap over the periods and an HashMap over the values
so that query performances are acceptable for queries in both dimensions even when
the collection is very large.