public DBRecord getRecordAtOrBefore(long key) throws IOException {
		synchronized (db) {
			if (rootBufferId < 0) {
				return null;
			}
			try {
				LongKeyRecordNode leaf = nodeMgr.getLongKeyNode(rootBufferId).getLeafNode(key);
				return leaf.getRecordAtOrBefore(key, schema);
			}
			finally {
				nodeMgr.releaseNodes();
			}
		}
	}
Get the record with the maximum key value which is less than or equal 
to the specified key.
@param key unique key which may or may not exist within the table.
@return the first record which has a key value less than or equal to the 
specified key, or null if no record was found.
@throws IOException throw if an IO Error occurs
Ghidra/Framework/DB/src/main/java/db/Table.java