Make it easier to perform side effects (such as toggling a progress view) in a Combine pipeline. See this Twitter conversation for context: https://twitter.com/DonnyWals/status/1506330967941820423

Publisher+handleEvents.swift

extension Publisher {
  
  /// Performs the specified closures when publisher events occur.
  ///
  /// This is an overloaded version of ``Publisher/handleEvents(receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:)`` 
  /// that only accepts a closure for the `receiveOutput` events. Use it to inspect events as they pass through the pipeline.
  ///
  /// - Parameters:
  ///   - receiveOutput: A closure that executes when the publisher receives a value from the upstream publisher.
  /// - Returns: A publisher that performs the specified closures when publisher events occur.
  func handleEvents(_ receiveOutput: (@escaping (Self.Output) -> Void)) -> Publishers.HandleEvents<Self> {
    self.handleEvents(receiveOutput: receiveOutput)
  }
  
  /// Performs the specified closures when publisher events occur.
  ///
  /// This is an overloaded version of ``Publisher/handleEvents(receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:)`` 
  /// that only accepts a closure for the `receiveOutput` events. Use it to execute side effects while events pass down the pipeline.
  ///
  /// - Parameters:
  ///   - receiveOutput: A closure that executes when the publisher receives a value from the upstream publisher.
  /// - Returns: A publisher that performs the specified closures when publisher events occur.
  func handleEvents(_ receiveOutput: (@escaping () -> Void)) -> Publishers.HandleEvents<Self> {
    self.handleEvents { output in
      receiveOutput()
    }
  }
  
}