Adds a value conceptually from a new random replica
Adding an element adds it to the current dot store as well as to the causal context (past).
Merging removes all elements the other side should known (based on the causal context), but does not contain.
Merging removes all elements the other side should known (based on the causal context), but does not contain. Thus, the delta for removal is the empty map, with the dot of the removed element in the context.