The request for
ListInstances][google.spanner.admin.instance.v1.InstanceAdmin.ListInstances].
Number of instances to be returned in the response. If 0 or
less, defaults to the server's maximum allowed page size.
An expression for filtering the results of the request. Filter
rules are case insensitive. The fields eligible for filtering
are: - name - display_name - labels.key where
key is the name of a label Some examples of using filters
are: - name:* --> The instance has a name. -
name:Howl --> The instance's name contains the string
"howl". - name:HOWL --> Equivalent to above. -
NAME:howl --> Equivalent to above. - labels.env:* -->
The instance has the label "env". - labels.env:dev -->
The instance has the label "env" and the value of the label
contains the string "dev". - name:howl labels.env:dev -->
The instance's name contains "howl" and it has the label
"env" with its value containing "dev".