@Override
	long getKey(int index) {
		return buffer.getLong(BASE + (index * ENTRY_SIZE));
	}
Perform a binary search to locate the specified key and derive an index
into the Buffer ID storage.  This method is intended to find the insertion 
index or exact match for a child key.  A negative value will be returned
when an exact match is not found and may be transformed into an 
insertion index (insetIndex = -returnedIndex-1).
@param key key to search for
@return int buffer ID index.
Ghidra/Framework/DB/src/main/java/db/LongKeyInteriorNode.java