feat(hono/context): add buffer returns #6111

Job	Run time
Main	20s
Checking if it's valid for JSR	10s
Bun	4s
Fastly Compute	1m 1s
Deno	17s
AWS Lambda	1m 0s
Lambda@Edge	1m 3s
Type & Bundle size Check on PR	1m 15s
Node.js v18.18.2	1m 10s
workerd	1m 8s
Node.js v20.x	1m 2s
Node.js v22.x	1m 2s
Type & Bundle size Check on Main	0s
Coverage	0s
	9m 32s

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