Consistency will define how a request is handled by the backend.
By defining a consistency requirement, and a token at which those
requirements should be applied, where applicable.

RelationshipFilter is a collection of filters which when applied to a
relationship will return relationships that have exactly matching fields.
resource_type is required. All other fields are optional and if left
unspecified will not filter relationships.

SubjectFilter specifies a filter on the subject of a relationship.
subject_type is required and all other fields are optional, and will not
impose any additional requirements if left unspecified.

ReadRelationshipsRequest specifies one or more filters used to read matching
relationships within the system.

ReadRelationshipsResponse contains a Relationship found that matches the
specified relationship filter(s). A instance of this response message will
be streamed to the client for each relationship found.

Precondition specifies how and the existence or absence of certain
relationships as expressed through the accompanying filter should affect
whether or not the operation proceeds.
MUST_NOT_MATCH will fail the parent request if any relationships match the
relationships filter.
MUST_MATCH will fail the parent request if there are no
relationships that match the filter.

WriteRelationshipsRequest contains a list of Relationship mutations that
should be applied to the service. If the optional_preconditions parameter
is included, all of the specified preconditions must also be satisfied before
the write will be committed.

Protobuf type authzed.api.v1.WriteRelationshipsResponse

DeleteRelationshipsRequest specifies which Relationships should be deleted,
requesting the delete of *ALL* relationships that match the specified
filters. If the optional_preconditions parameter is included, all of the
specified preconditions must also be satisfied before the delete will be
executed.

Protobuf type authzed.api.v1.DeleteRelationshipsResponse

CheckPermissionRequest issues a check on whether a subject has a permission
or is a member of a relation, on a specific resource.

Protobuf type authzed.api.v1.CheckPermissionResponse

ExpandPermissionTreeRequest returns a tree representing the expansion of all
relationships found accessible from a permission or relation on a particular
resource.
ExpandPermissionTreeRequest is typically used to determine the full set of
subjects with a permission, along with the relationships that grant said
access.

Protobuf type authzed.api.v1.ExpandPermissionTreeResponse

LookupResourcesRequest performs a lookup of all resources of a particular
kind on which the subject has the specified permission or the relation in
which the subject exists, streaming back the IDs of those resources.

LookupResourcesResponse contains a single matching resource object ID for the
requested object type, permission, and subject.

LookupSubjectsRequest performs a lookup of all subjects of a particular
kind for which the subject has the specified permission or the relation in
which the subject exists, streaming back the IDs of those subjects.

LookupSubjectsResponse contains a single matching subject object ID for the
requested subject object type on the permission or relation.