title: What is Content in SwiftUI?
body: <p>In the documentation, I see <code>Content</code> in a different context:</p>
  
  <pre><code>/// A modifier that can be applied to a view or other view modifier,
  /// producing a different version of the original value.
  @available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
  public protocol ViewModifier {
      /// The content view type passed to `body()`.
      typealias Content
  }
  </code></pre>
  
  <p>and here</p>
  
  <pre><code>/// A view that arranges its children in a vertical line.
  @available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
  public struct VStack&lt;Content&gt; where Content : View {
  </code></pre>
  
  <p>I can't find in the documentation the proper explanation of what does  <code>Content</code> mean. Is there any predefined <code>content</code> usage in SwiftUI?</p>