enhance: ActivityPub 周りで 429 を受け取った際にリトライするように (MisskeyIO#324)

packages/backend/src/misc/status-error.ts

@@ -7,6 +7,7 @@ export class StatusError extends Error {
 	public statusCode: number;
 	public statusMessage?: string;
 	public isClientError: boolean;
+	public isRetryable: boolean;
 
 	constructor(message: string, statusCode: number, statusMessage?: string) {
 		super(message);
@@ -14,5 +15,6 @@ export class StatusError extends Error {
 		this.statusCode = statusCode;
 		this.statusMessage = statusMessage;
 		this.isClientError = typeof this.statusCode === 'number' && this.statusCode >= 400 && this.statusCode < 500;
+		this.isRetryable = !this.isClientError || this.statusCode === 429;
 	}
 }