Like getRecomputedSizeInBytes(), but, uses actual file
lengths rather than buffer allocations (which are
quantized up to nearest
RAMOutputStream.BUFFER_SIZE (now 1024) bytes.
Used by MockRAMDirectory to create an output stream that
will throw an IOException on fake disk full, track max
disk space actually used, and maybe throw random
IOExceptions.
Given a Searcher, returns a new MultiSearcher wrapping the
the original Searcher,
as well as several "empty" IndexSearchers -- some of which will have
deleted documents in them.
Given an IndexSearcher, returns a new IndexSearcher whose IndexReader
is a MultiReader containing the Reader of the original IndexSearcher,
as well as several "empty" IndexReaders -- some of which will have
deleted documents in them.