Adds an entry to the map. Note that the new value will be merged with existing values on other nodes and the outcome depends on what IReplicatedData type that is used. Consider using AddOrUpdate(Cluster, TKey, TValue, FuncTValue, TValue) instead of SetItem(Cluster, TKey, TValue) if you want modify existing entry. ArgumentException is thrown if you try to replace an existing ORSetT value, because important history can be lost when replacing the `ORSet` and undesired effects of merging will occur. Use ORMultiDictionaryTKey, TValue or AddOrUpdate(Cluster, TKey, TValue, FuncTValue, TValue) instead.

Adds an entry to the map. Note that the new value will be merged with existing values on other nodes and the outcome depends on what IReplicatedData type that is used. Consider using AddOrUpdate(Cluster, TKey, TValue, FuncTValue, TValue) instead of SetItem(UniqueAddress, TKey, TValue) if you want modify existing entry. ArgumentException is thrown if you try to replace an existing ORSetT value, because important history can be lost when replacing the `ORSet` and undesired effects of merging will occur. Use ORMultiDictionaryTKey, TValue or AddOrUpdate(Cluster, TKey, TValue, FuncTValue, TValue) instead.