A not so documented feature is the support of VMXNET3 in VMWare Fusion. It cannot be configured through the UI but by manually editing the VM configuration file (VMX-file), you can leverage it (assuming you have installed VMWare Tools and/or are running a supported guest OS).
Open the file with your favourite text editor, but avoid using Apple's TextEdit as it has a tendency to replace regular quotes with opening/closing quotes, which will break your VMX-file. You can use Terminal and open the file using Nano if you want to be sure.
Network adapters are specified with ethernet*. as the starting line, where * = the number of the network adapter (0 is the first, 1 is the second, and so on). The parameter ethernet*.virtualDev of each adapter specifies the virtual hardware type for that adapter. Depending on the configured guest OS and virtual hardware version, this will be set to something compatibel. Possible options usually are:
By editing the ethernet*.virtualDev parameter and adjusting the value to the desired device type, you can switch the virtual network adapter to the type you want to have.
For example, you can change the adapter from Intel E1000 to VMXNET3 by editing the parameter:
ethernet0.virtualDev="e1000" → ethernet0.virtualDev="vmxnet3"
Note that for this to work, the VM needs to be powered off when editing the configuration file.