private Item newString(final String value) {
        key2.set(8 /* STR */, value, null, null);
        Item result = get(key2);
        if (result == null) {
            pool.put12(8 /*STR*/, newUTF8(value));
            result = new Item(index++, key2);
            put(result);
        }
        return result;
    }
Adds a method reference to the constant pool of the class being build. Does nothing if the constant pool already
contains a similar item.

@param owner the internal name of the method's owner class.
@param name the method's name.
@param desc the method's descriptor.
@param itf <tt>true</tt> if <tt>owner</tt> is an interface.
@return a new or already existing method reference item.
src/main/java/com/alibaba/fastjson/asm/ClassWriter.java