fix post request hangs when no body is consumed on middleware

[nkzawa]

fixes #34966

Wait for reading original request body before overwriting the request properties with originalBody?.finalize() call since it caused the problem when middleware does not read request body

Bug

• Related issues linked using fixes #number
• Integration tests added
• Errors have helpful link attached, see contributing.md

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
buildDuration	15.8s	15.8s	⚠️ +30ms
buildDurationCached	6.1s	6.1s	-11ms
nodeModulesSize	367 MB	372 MB	⚠️ +5.28 MB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.098	3.13	⚠️ +0.03
/ avg req/sec	807.03	798.65	⚠️ -8.38
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.348	1.366	⚠️ +0.02
/error-in-render avg req/sec	1853.94	1830.33	⚠️ -23.61

Client Bundles (main, webpack)

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
925.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	27.9 kB	27.9 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.5 kB	71.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
_app-HASH.js gzip	1.36 kB	1.36 kB	✓
_error-HASH.js gzip	192 B	192 B	✓
amp-HASH.js gzip	309 B	309 B	✓
css-HASH.js gzip	327 B	327 B	✓
dynamic-HASH.js gzip	2.57 kB	2.57 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	920 B	920 B	✓
image-HASH.js gzip	5.09 kB	5.09 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.26 kB	2.26 kB	✓
routerDirect..HASH.js gzip	320 B	320 B	✓
script-HASH.js gzip	387 B	387 B	✓
withRouter-HASH.js gzip	319 B	319 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	14.8 kB	14.8 kB	✓

Client Build Manifests

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
index.html gzip	530 B	530 B	✓
link.html gzip	544 B	544 B	✓
withRouter.html gzip	524 B	524 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
buildDuration	18.8s	18.8s	-29ms
buildDurationCached	6s	6.2s	⚠️ +217ms
nodeModulesSize	367 MB	372 MB	⚠️ +5.28 MB

Page Load Tests Overall increase ✓

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.106	3.116	⚠️ +0.01
/ avg req/sec	804.97	802.41	⚠️ -2.56
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.359	1.356	0
/error-in-render avg req/sec	1839.04	1843.35	+4.31

Client Bundles (main, webpack)

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
925.HASH.js gzip	178 B	178 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	28.2 kB	28.2 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	72.1 kB	72.1 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	179 B	179 B	✓
amp-HASH.js gzip	313 B	313 B	✓
css-HASH.js gzip	324 B	324 B	✓
dynamic-HASH.js gzip	2.56 kB	2.56 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	921 B	921 B	✓
image-HASH.js gzip	5.23 kB	5.23 kB	✓
index-HASH.js gzip	261 B	261 B	✓
link-HASH.js gzip	2.33 kB	2.33 kB	✓
routerDirect..HASH.js gzip	322 B	322 B	✓
script-HASH.js gzip	388 B	388 B	✓
withRouter-HASH.js gzip	317 B	317 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	15 kB	15 kB	✓

Client Build Manifests

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	nkzawa/next.js middleware-post-hang	Change
index.html gzip	532 B	532 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: a79e9d4