A single operation (create, update) on a conversion custom variable.
| Fields | |
|---|---|
| 
 | FieldMask that determines which resource fields are modified in an update. | 
| Union field 
 | |
| 
 | Create operation: No resource name is expected for the new conversion custom variable. | 
| 
 | Update operation: The conversion custom variable is expected to have a valid resource name. |