private SymbolRecords.SymLen retrieveRecord() {
		if (streamNumber == MsfStream.NIL_STREAM_NUMBER) {
			return null;
		}
		if (nextRetrieveOffset >= lengthSymbols) {
			return null;
		}
		try {
			SymbolRecords.SymLen retrieved =
				symbolRecords.getRandomAccessRecord(streamNumber, nextRetrieveOffset);
			if (retrieved != null) {
				nextRetrieveOffset += retrieved.length();
			}
			return retrieved;
		}
		catch (PdbException | CancelledException e) {
			return null;
		}
	}
Peeks at and returns the next symbol without incrementing to the next.  If none are
left, then throws NoSuchElementException and reinitializes the state for a new
iteration.
@see #initGet()
@return the next symbol
@throws NoSuchElementException if there are no more elements
Ghidra/Features/PDB/src/main/java/ghidra/app/util/bin/format/pdb2/pdbreader/MsSymbolIterator.java