A singleton for managing [NavigationServer2D] implementations.
[NavigationServer2DManager] is the API for registering [NavigationServer2D] implementations and setting the default implementation. [b]Note:[/b] It is not possible to switch servers at runtime. This class is only used on startup at the server initialization level.
Registers a [NavigationServer2D] implementation by passing a [param name] and a [Callable] that returns a [NavigationServer2D] object.
Sets the default [NavigationServer2D] implementation to the one identified by [param name], if [param priority] is greater than the priority of the current default implementation.