Magento 2.1:- Create Plugin but not working in custom module

Question

I create plugin in my custom module to override the method collectCarrierRates($carrierCode, $request), below code is not working. What mistake here?

app/code/Vendor/Shippingtest/etc/frontend/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Shipping\Model\Shipping">
        <plugin name="vendor-shippingtest-test"
                type="Vendor\Shippingtest\Plugin\Test"
                sortOrder="10"/>
    </type>
</config>

app/code/Vendor/Shippingtest/Plugin/Test.php

<?php

namespace Vendor\Shippingtest\Plugin;

class Test
{
    public function after(Magento\Shipping\Model\Shipping $subject, $result)
    {
        echo "Calling";
    }
}

Answer 1

I'm not entirely sure what you're trying to achieve but there's a major problem in your method name, it does not contain the name of the original method.

You should replace:

public function after(Magento\Shipping\Model\Shipping $subject, $result)

With:

public function afterCollectCarrierRates(Magento\Shipping\Model\Shipping $subject, $result)

So your plugin can work.