Function createMetrics

Returns {
    recordBlockExecuted(durationMs: number, cost: number): void;
    recordBlockExecutionFailed(reason: string): void;
    recordBlockImportComplete(totalDurationMs: number, success: boolean): void;
    recordBlockImportingStarted(slot: number): void;
    recordBlockVerificationFailed(reason: string): void;
    recordBlockVerified(durationMs: number): void;
}