Initial: Standalone mixer app with MixerPage, scene management, WS proxy

backend/venv/lib/python3.11/site-packages/uvloop/handles/check.pxd

@@ -0,0 +1,14 @@
+cdef class UVCheck(UVHandle):
+    cdef:
+        Handle h
+        bint running
+
+    # All "inline" methods are final
+
+    cdef _init(self, Loop loop, Handle h)
+
+    cdef inline stop(self)
+    cdef inline start(self)
+
+    @staticmethod
+    cdef UVCheck new(Loop loop, Handle h)