@Override
	public String toString() {
		return String.format("%s: num checksums = %d", getClass().getSimpleName(),
			fileChecksums.size());
	}
Returns the C13 file checksum for the offset of the record in the checksum table
@param offset the offset of the record
@return the checksum or null if record not found
Ghidra/Features/PDB/src/main/java/ghidra/app/util/bin/format/pdb2/pdbreader/FileChecksumsC13Section.java