Why using a different Conv4?

[z1358]

Dear author,
As far as I know, Conv4 in many literatureas refers to four convolutional blocks, each of which consists of a convolutional layer, a batch normalization layer, a Leaky ReLU layer and a 2×2 max-pooling layer. Why do you remove the max-pooling layer of the last layer and use a self.avgpool = nn.AdaptiveAvgPool2d(1)?
Looking forword to your reply.