createNotebookCellExecution
Create a cell execution task.
Note that there can only be one execution per cell at a time and that an error is thrown if a cell execution is created while another is still active.
This should be used in response to the execution handler being called or when cell execution has been started else, e.g when a cell was already executing or when cell execution was triggered from another source.
Parameters
cell
The notebook cell for which to create the execution.