title: How to drag a working slider using SwiftUI
body: <p>I would like to drag a slider and of course have it slide as well.
  I can do one or the other, but I cannot do both.
  How can I drag and have a working slider?</p>
  
  <p>I also tried to find a way to remove a gesture, but I could not find a way to do that.
  Also tried the "Sequenced Gesture States" code from Apple "Composing SwiftUI Gestures" docs,
  and introduce a flag to turn the dragging on/off with same results, drag or slide not both.</p>
  
  <p>I also tried to put the slider in a Container (VStack) and attach the drag gesture to that, 
  but that did not work either.  </p>
  
  <pre><code>import SwiftUI
  
  struct ContentView: View {
  @State var pos = CGSize.zero
  @State var acc = CGSize.zero
  @State var value = 0.0
  
  var body: some View {
      let drag = DragGesture()
          .onChanged { value in
              self.pos = CGSize(width: value.translation.width + self.acc.width, height: value.translation.height + self.acc.height)
      }
      .onEnded { value in
          self.pos = CGSize(width: value.translation.width + self.acc.width, height: value.translation.height + self.acc.height)
          self.acc = self.pos
      }
  
      return Slider(value: $value, in: 0...100, step: 1)
          .frame(width: 250, height: 40, alignment: .center)
          .overlay(RoundedRectangle(cornerRadius: 25).stroke(lineWidth: 2).foregroundColor(Color.black))
          .offset(x: self.pos.width, y: self.pos.height)
          .simultaneousGesture(drag, including: .all)  // tried .none .gesture, .subviews
          // also tried .gesture(flag ? nil : drag)
  }
  }
  </code></pre>
  
  <p>With "simultaneousGesture" I was expecting to have both gestures operating at the same time.</p>