message: Add iterators and size() helper method in ArrayAttr
diff: @@ -222,6 +222,12 @@ public:
  ArrayRef<Attribute> getValue() const;
  + size_t size() const { return getValue().size(); }
  +
  + using iterator = llvm::ArrayRef<Attribute>::iterator;
  + iterator begin() const { return getValue().begin(); }
  + iterator end() const { return getValue().end(); }
  +
  /// Methods for support type inquiry through isa, cast, and dyn_cast.
  static bool kindof(Kind kind) { return kind == Kind::Array; }
  };
  