https://docs.unity3d.com/Manual/UNetStateSync.html …see red text below.
SyncLists
SyncLists are like SyncVars but they are lists of values instead of individual values. SyncList contents are included in initial state updates with SyncVar state. SyncLists do not require the SyncVar attributes, they are specific classes. There are built-in SyncList types for basic types:
- SyncListString
- SyncListFloat
- SyncListInt
- SyncListUInt
- SyncListBool
There is also SyncListStruct which can be used for lists of user-defined structs. The struct used SyncListStruct derived class can contain members of basic types, arrays, and common Unity types. They cannot contain complex classes or generic containers.
SyncLists have a SyncListChanged delegate named Callback that allows clients to be notified when the contents of the list change. This delegate is called with the type of operation that occurred, and th eindex of the item that the operation was for.