Read one member.
signal is ADVISORY. A container whose reader has no per-call channel — a
zip, whose unzipit reader is read(offset, size) — cannot cancel an
individual member read, and an ambient "current signal" would be raced by
concurrent gets. Such an implementation scopes real cancellation to its own
lifetime instead, aborting in flight reads from dispose(), and uses this
signal only to stop early and to label the outcome. Do not read a passed
signal as a guarantee that the bytes stopped arriving.
Optionalsignal: AbortSignalOptionalprobeFresh identity of the container, bypassing caches — an opaque token, so
this layer needs to know nothing about ETags or HTTP. null means "cannot
tell", which is never evidence of a change.
The container answers this rather than the caller because it is a request
against the same URL the container already reads: doing it here lets one
HEAD serve both identity and the archive length.
Optionalsignal: AbortSignalOptionaltimeoutMs: number
The minimum a byte-container has to offer for ChunkSource to read it.
Declared HERE, and injected, rather than importing a concrete store:
src/cachesits belowsrc/datain the layer order, so the cache layer must not reach up fordata/zip/store. The cache defines the port; the data layer supplies the adapter. It also keeps this module ignorant of zip specifics entirely.