Guard with use_pending_kernels

Author: jtpio

jupyter_server/services/kernels/kernelmanager.py

@@ -210,7 +210,9 @@ async def start_kernel(self, kernel_id=None, path=None, **kwargs):
                 kwargs["kernel_id"] = kernel_id
             kernel_id = await ensure_async(self.pinned_superclass.start_kernel(self, **kwargs))
             self._kernel_connections[kernel_id] = 0
-            await asyncio.ensure_future(self._finish_kernel_start(kernel_id))
+            fut = asyncio.ensure_future(self._finish_kernel_start(kernel_id))
+            if not getattr(self, "use_pending_kernels", None):
+                await fut
             # add busy/activity markers:
             kernel = self.get_kernel(kernel_id)
             kernel.execution_state = "starting"