ConstReadonlyexceedsBudget: "insert.latency.exceeds-budget"The chain's latency is over the destination's budget, with everything resolved.
ReadonlymayExceedBudget: "insert.latency.may-exceed-budget"The chain COULD be over budget: a parameter-dependent plugin's span straddles it.
ReadonlyunknownAtRate: "insert.latency.unknown-at-rate"At least one plugin's latency could not be resolved at this rate, so no total exists.
ReadonlywithinBudget: "insert.latency.within-budget"The chain fits. Carried so the surface can show the headroom, not only the failures.
The message CODES a latency judgement speaks. Codes, not prose: the client renders the sentence in the operator's locale from the code plus LatencyBudgetParams.