ISO 8601 timestamp for the last-seen activity on this kernel.
Use this in combination with execution_state == 'idle' to identify
which kernels have been idle since a given time.
Timestamps will be UTC, indicated 'Z' suffix.
Added in notebook server 5.0.
connectionsnumber
The number of active connections to this kernel.
execution_statestring
Current execution state of the kernel (typically 'idle' or 'busy', but may be other values, such as 'starting').
Added in notebook server 5.0.