FIX/REF: Continue handling foreign iopub after kernel is switched.
FIX/REF: Continue handling foreign iopub after kernel is switched.

charnpreetsingh185/jupyterlab,jupyter/jupyterlab,charnpreetsingh185/jupyterlab,eskirk/jupyterlab,jupyter/jupyterlab,charnpreetsingh185/jupyterlab,jupyter/jupyterlab,eskirk/jupyterlab,charnpreetsingh185/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,eskirk/jupyterlab,eskirk/jupyterlab,charnpreetsingh185/jupyterlab,eskirk/jupyterlab