note_stalled: TxDescriptor<{
    best_finalized_block_number: number;
    delay: number;
}>

Note that the current authority set of the GRANDPA finality gadget has stalled.

This will trigger a forced authority set change at the beginning of the next session, to be enacted delay blocks after that. The delay should be high enough to safely assume that the block signalling the forced change will not be re-orged e.g. 1000 blocks. The block production rate (which may be slowed down because of finality lagging) should be taken into account when choosing the delay. The GRANDPA voters based on the new authority will start voting on top of best_finalized_block_number for new finalized blocks. best_finalized_block_number should be the highest of the latest finalized block of all validators of the new authority set.

Only callable by root.