code: @Override
      public void visitMethod(Method obj) {
          if (localizableFields.isEmpty()) {
              return;
          }
  
          try {
  
              cfg = clsContext.getCFG(obj);
              cpg = cfg.getMethodGen().getConstantPool();
              BasicBlock bb = cfg.getEntry();
              Set<String> uncheckedFields = new HashSet<>(localizableFields.keySet());
              visitedBlocks.clear();
              checkBlock(bb, uncheckedFields);
          } catch (CFGBuilderException cbe) {
              localizableFields.clear();
          } finally {
              cfg = null;
              cpg = null;
          }
      }
docs: overrides the visitor to navigate basic blocks looking for all first usages of fields, removing those that are read from first.
  
  @param obj
  the context object of the currently parsed method