OptionalfetchOptionalinit: RequestInitOptionalinit: RequestInitOptionalfetchCaps a single physical fetch issued on a cache miss past the open
prefetch. Defaults to DEFAULT_FETCH_SIZE (1 MB).
OptionalsignalAborts every request this reader issues, at any point in its
lifetime -- the one made by open() and every later read(). Wired
directly into the underlying fetch() call so a signal that fires
mid-flight actually cancels the in-progress request; an
already-aborted signal is also honoured before any work starts.
Injection point for tests (a counting wrapper) and environments without a global
fetch. Defaults toglobalThis.fetch.