The typedef PortPanEndCallback = void Function(DragEndDetails details); line in the code is
defining a function type alias in Dart. It creates an alias PortPanEndCallback for a function that
takes one parameter details of type DragEndDetails and returns void. This allows you to define
functions with this specific signature and use them as callbacks in your code where
PortPanEndCallback type is expected.
The typedef PortPanStartCallback is defining a function type in Dart. It is creating an alias
PortPanStartCallback for a function that takes three parameters: portIndex of type int,
isOutput of type bool, and details of type DragStartDetails, and returns void. This allows
you to define functions with this signature and use them as callbacks in your code.
The typedef PortPanUpdateCallback = void Function(DragUpdateDetails details); line in the code is
defining a function type alias in Dart. It creates an alias PortPanUpdateCallback for a function
that takes one parameter details of type DragUpdateDetails and returns void. This allows you
to define functions with this specific signature and use them as callbacks in your code where
PortPanUpdateCallback type is expected.
