Clarify how `network_interface` in `customize` blocks are assigned

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Description

It's mentioned in the docs that multiple network interfaces can be customized when cloning:

https://github.com/hashicorp/terraform-provider-vsphere/blob/0c2be2d0c2d769b982bc50c6798e08249121bda1/website/docs/r/virtual_machine.html.markdown?plain=1#L1130

The first network_interface would be assigned to the public interface, and the second to the private interface.

It is, however, never explained why this works. Is the first network interface assigned to the public interface because of the order it is defined in or because the IP matches the network or something else?

Use Case(s)

Docs should explain how to use the provider.

Potential Terraform Provider Configuration

No response

References