concatMap((action: actions.KillKernelAction) => {
      const state = state$.value;

      const host = selectors.currentHost(state);
      if (host.type !== "jupyter") {
        // Dismiss any usage that isn't targeting a jupyter server
        return empty();
      }
      const serverConfig: ServerConfig = selectors.serverConfig(host);

      const kernel = selectors.currentKernel(state);
      if (!kernel) {
        return of(
          actions.killKernelFailed({
            error: new Error("kernel not available for killing"),
            kernelRef: action.payload.kernelRef
          })
        );
      }

      if (kernel.type !== "websocket" || !kernel.id || !kernel.sessionId) {
        return of(
          actions.killKernelFailed({
            error: new Error(
              "websocket kernel epic can only kill websocket kernels with an id"
            ),
            kernelRef: action.payload.kernelRef
          })
        );
      }

      // TODO: If this was a kernel language change, we shouldn't be using this
      //       kill kernel epic because we need to make sure that creation happens
      //       after deletion
      return sessions.destroy(serverConfig, kernel.sessionId).pipe(
        map(() =>
          actions.killKernelSuccessful({
            kernelRef: action.payload.kernelRef
          })
        ),
        catchError(err =>
          of(
            actions.killKernelFailed({
              error: err,
              kernelRef: action.payload.kernelRef
            })
          )
        )
      );
    })

 catchError(err =>
   of(
     actions.killKernelFailed({
       error: err,
       kernelRef: action.payload.kernelRef
     })
   )