[orut34iop]

Hosts can choose a forward window but cannot request an exact temporary VOD cache budget or tell whether cleanup succeeded. Add optional LoadOptions.sessionCacheByteBudget and a separate EngineDiagnostics.sessionCacheStatus snapshot with requested/effective budgets, resident bytes, protected-window overflow, producer parking, eviction and typed cleanup/failure results.

Nil preserves existing automatic sizing. Explicit requests reuse the quarter-of-available-space safeguard and RetentionClaims allocation after other sessions' unwritten claims. Unknown capacity keeps the conservative ceiling. Zero keeps the necessary working window rather than promising zero I/O; the software disk path keeps a bounded working spool. A protected fMP4 playback window may exceed the request, which the snapshot reports explicitly. The tvOS memory default and live DVR policy remain unchanged; live reports this VOD byte policy as unsupported.

State is sampled off-main from the segment ledger at the existing telemetry cadence. Cleanup may publish after stop, but session tokens reject callbacks from a superseded load/rebuild and an old startup callback cannot revive a stopped cache. Remote HLS is reported as AVPlayer/server managed, not successful zero-byte caching. Detailed snapshots cover fMP4 segment caching; software packets retain their existing telemetry.

Keep the existing #720 ENOSPC classification and #714 live DVR limits. A bounded stale-directory sweep retains the liveness marker, reports enumeration/deletion failures, and never reuses another session's bytes. This is not the cross-launch source cache discussed in #706. No UI settings or host-specific cache tiers are included.

This is independent of #827 (explicit packet-store selection), but both touch SoftwarePlaybackHost construction and the LoadOptions inventory. If #827 lands first, the requested-byte resolution belongs inside its disk factory; the memory branch and automatic platform choice must stay unchanged. No combined-branch or device performance acceptance is claimed.

Tests cover default equivalence, explicit/zero/unknown capacity, shared claims, actual segment writes and replacements, parking, hard-window overflow, bounded sweep, failed directory/write/adoption/cleanup, real engine load/stop cleanup and rejection of old-session updates.

Validation: 66 focused tests under the strict cooperative pool passed. Full serial host suite passed: 795 XCTest tests (1 existing skip) and 4,636 Swift Testing tests across 637 suites. Published documentation links and git diff --check passed. Existing Issue451 creation-time/liveness assertions remain unchanged, and a callback-type regression preserves the public zero-argument HLSVideoEngine.stop() API. Platform and optional-trait validation is left to CI; no new device acceptance is claimed.

[superuser404notfound]

Merged in 7e4fd030, thanks @orut34iop. The status snapshot and the session token handling are a clean piece of work, and the tests cover the lifecycle well.

The branch predated #827, #829 and #348, so the merge resolved eight conflicts: the requested byte budget now goes through makePacketStore's disk branch from #827 (memory branch and .automatic unchanged, as the description anticipated), and the AE#348 prepare / serve split stops with .loadFailed on failure like start() does.

Follow-ups on main:

• 2d63474a: an explicit budget of 0 reached SegmentCache, PrefetchDiskBudget and the window sizing as 0, which all three read as "no byte bound". With a large forwardBufferSegments that dropped the producer park and the quarter-of-free-space clamp instead of keeping only the window. An explicit request now enforces at least 1 byte (SessionCacheBudgetResolution.enforcedBytes); the status still reports the clamped request. Same for a request the volume clamp reduces to zero. Also restores the AE#451 ordering comment and the spared-live-dir log line in the sweep, and moves the changelog entry into Unreleased.
• b3f3e9d2: no force unwrap on the resolved budget, and a stale directory whose creation date cannot be read is sweepable again as before the rewrite (liveness still spares a held one).

Full suite green after each step (780 XCTest, 4753 Swift Testing). Ships with the next engine release.

[superuser404notfound]

Released in 7.45.0 (52802af).