The synchronous stand-in for \Fiber that the patched tree expects. A real Fiber aborts the
runtime ("missing function: getcontext": emscripten has no ucontext), so
scripts/patch-drupal.mjs rewrites core's five call sites to this class, which must exist before
Drupal loads. One definition for every fragment: the class_exists guard lets whichever runs
first declare it.
The synchronous stand-in for
\Fiberthat the patched tree expects. A real Fiber aborts the runtime ("missing function: getcontext": emscripten has no ucontext), soscripts/patch-drupal.mjsrewrites core's five call sites to this class, which must exist before Drupal loads. One definition for every fragment: theclass_existsguard lets whichever runs first declare it.