The sorted array to search.
The pattern to search for.
The evaluation predicate, which should return true if e1 is less than e2 and false if not. This predicate may be any callable type.
The index of the first match or buf.length if no match was found.
Performs a binary search of buf, returning the index of the first location beyond where pat may be inserted without disrupting sort order. If the sort order of pat precedes all elements in buf then 0 will be returned. If the sort order of pat succeeds the largest element in buf then buf.length will be returned. Comparisons will be performed using the supplied predicate or '<' if none is supplied.