Issue #3412168 by godotislate, catch, smustgrave, longwave: Add back "final" to Drupal\big_pipe\StackMiddleware\ContentLength

Issue #3338328 by Spokje, andypost, longwave, effulgentsia, jungle, catch, smustgrave, Wim Leers: Update to Symfony 6.3

Issue #3258902 by longwave, Spokje, catch, daffie: [Symfony 6] Bring stackphp/builder into core for Symfony 6 compatibility and remove it as a dependency

Issue #3222251 by bbrala, longwave: [November 8, 2021] Replace all isset constructs with the null coalescing operator

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2473113 by znerol, dpovshed, Wim Leers, Fabianx, dawehner, effulgentsia: All stack middlewares are constructed at the same time even for cached pages

Issue #2343677 by damiankloip, znerol, Fabianx, pounard: Fixed Stack middleware suffers from incomplete service construction.

This reverts commit 39eb84fc.

Revert "Issue #2343677 by damiankloip, znerol, Fabianx: Fixed Stack middleware suffers from incomplete service construction."

This reverts commit c033857b.

Issue #2343677 by damiankloip, znerol, Fabianx: Fixed Stack middleware suffers from incomplete service construction.

Issue #2303673 by dawehner, damiankloip, effulgentsia, Fabianx: Implement stackphp; cleanup handlePageCache() and preHandle()