merge(with:)
Declaration
func merge<P>(with other: P) -> Publishers.Merge4<A, B, C, P> where P : Publisher, C.Failure == P.Failure, C.Output == P.Outputfunc merge<P>(with other: P) -> Publishers.Merge4<A, B, C, P> where P : Publisher, C.Failure == P.Failure, C.Output == P.Output