[2108] Add another item to TODO list

src/lib/datasrc/memory/tests/memory_client_unittest.cc

@@ -295,4 +295,5 @@ TEST_F(MemoryClientTest, getJournalReaderNotImplemented) {
 // Add test for add() with separate_rrs=true
 // Add test for ZoneIterator variant of load()
 // Add test for leaks during allocation failures using TestMemorySegment
+// Iterate through an entire zone
 }