A singleton for managing [PhysicsServer3D] implementations.
[PhysicsServer3DManager] is the API for registering [PhysicsServer3D] implementations and for setting the default implementation. [b]Note:[/b] It is not possible to switch physics servers at runtime. This class is only used on startup at the server initialization level, by Godot itself and possibly by GDExtensions.
Register a [PhysicsServer3D] implementation by passing a [param name] and a [Callable] that returns a [PhysicsServer3D] object.
Set the default [PhysicsServer3D] implementation to the one identified by [param name], if [param priority] is greater than the priority of the current default implementation.