Very few situations require only observation and no need to do anything when the signal is received

Publisher+SinkExtension.swift

import Combine

extension Publisher {
    
    public func sink(completion completionHandle: (() -> Void)? = nil, receiveError: ((Self.Failure) -> Void)? = nil, receiveValue: ((Self.Output) -> Void)? = nil) -> AnyCancellable {
        return self.sink(receiveCompletion: { completion in
            switch completion {
            case .failure(let error):
                receiveError?(error)
            case .finished:
                completionHandle?()
            }
        }, receiveValue: { value in
            receiveValue?(value)
        })
    }
}