method MemoryTable.prototype.onBeforeChangeimport { MemoryTable } from "https://dotland.deno.dev/x/pg_mem@3.0.2/table.ts"; onBeforeChange(columns: "all" | (string | _Column)[], check: ChangeHandler): ISubscriptionParameterscolumns: "all" | (string | _Column)[]check: ChangeHandlerReturnsISubscription