The types of operations that can occur for SyncLists.
| OP_ADD | Item was added to the list. |
| OP_CLEAR | The list was cleared. |
| OP_INSERT | An item was inserted into the list. |
| OP_REMOVE | An item was removed from the list. |
| OP_REMOVEAT | An item was removed at an index from the list. |
| OP_SET | An item was set to a new value in the list. |
| OP_DIRTY | An item in the list was manually marked dirty. |