`rawBody` can be undefined but it's typed as a string

[btabram]

Hello, just wondering if this is intentional or not? It feels misleading and like it could lead to runtime bugs

rawBody is declared as a string:

bodyparser/src/body-parser.ts

Lines 9 to 15 in 7e1ded3

	declare module 'koa' {
	// eslint-disable-next-line @typescript-eslint/consistent-type-definitions
	interface Request {
	body?: unknown;
	rawBody: string;
	}
	}

but in practice it will be undefined if a suitable body type is not found:

bodyparser/src/body-parser.ts

Line 60 in 7e1ded3

if (!bodyType) return {} as Record<string, string>;

Thank you!

[btabram]

I'm very happy to make a PR if this is something you're open to changing!