     /// Default value
     var preload: CGFloat { return 0 }
     var isVisibleNoMore: Bool { return true }
+    var isOnlyRefreshPerDrag: Bool { return true }
     var loadMoreInsets: UIEdgeInsets { return .zero }
     
 }

            }
        }
    }
    
    // MARK: Helper Properties
    

    /// When there is no more data, is it necessary to keep the height of the custom view? If it is false, it will not be displayed.
    var isVisibleNoMore: Bool { get }
    
    /// @optional, default is true.
    /// Whether to send a request only once per drag. If it is false, it will be called continuously when the offset changes.
    var isOnlyRefreshPerDrag: Bool { get }
    
    /// @optional, default is .zero.
    /// -top: increase the distance from scrollview.
    /// -left and right: set the horizontal offset.
