pub const RETRY_EXEMPLAR_RATE: ControlDesc;Expand description
retry_exemplar_rate — retry-error counter-exemplar sampling
(SRD-82 Part 3b / exec_events). Push-on-set: the applier is one
atomic store into the activity’s shared ExemplarConfig; samplers
read it only on their retry path. Ops that pin retry_exemplar_*
params hold private cells this control does not move.