applyMutation = function applyMutation (target, mutation) {
        // only `set` and `unset` instructions are supported
        // for non primitive mutations, the instruction would have to be extracted from mutation
        /* istanbul ignore if */
        if (!isPrimitiveMutation(mutation)) {
            return;
        }

        // extract instruction from the mutation
        var operation = mutation.length > 1 ? PRIMITIVE_MUTATIONS.SET : PRIMITIVE_MUTATIONS.UNSET;

        // now hand over applying mutation to the target
        target.applyMutation(operation, ...mutation);
    }
Applies a single mutation on a target.

@private
@param {*} target -
@param {MutationTracker.mutation} mutation -