The endpoint type of this address, which should be VM or
NETLB. This is used for deciding which type of endpoint this
address can be used after the external IPv6 address reservation.
Values:
UNDEFINED_IPV6_ENDPOINT_TYPE (0):
A value indicating that the enum field is not
set.
NETLB (74173363):
Reserved IPv6 address can be used on network
load balancer.
VM (2743):
Reserved IPv6 address can be used on VM.
