private Item get(final Item key) {
        Item i = items[key.hashCode % items.length];
        while (i != null && (i.type != key.type || !key.isEqualTo(i))) {
            i = i.next;
        }
        return i;
    }
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