A single operation (create, remove) on a customizer attribute.
| Fields | |
|---|---|
| 
 | FieldMask that determines which resource fields are modified in an update. | 
| Union field 
 | |
| 
 | Create operation: No resource name is expected for the new customizer attribute | 
| 
 | 
 Remove operation: A resource name for the removed customizer attribute is expected, in this format:  |