backendGroup property
A fully-qualified URL (starting with https://www.googleapis.com/)
of the zonal Network Endpoint Group (NEG) with GCE_VM_IP endpoints
that the leader is attached to.
The leader's backendGroup must already be specified as a backend of this backend service.
Removing a backend that is designated as the leader's backendGroup is not permitted.
Implementation
core.String? backendGroup;