OwnedBytesHandle

Opaque, platform-typed handle for bytes that need to outlive the wire frame they were decoded from — IPC forwarding, persistence, debug capture, default-decode for payloads whose codec isn't pinned at decode time.

Shape: the canonical Pattern #2 from the buffer-codec lockdown plan (consumer-owned PlatformBuffer allocated via factory.allocate(...) + write(source)). The handle's actual stores a PlatformBuffer internally on every platform; the expect class boundary is what shields KSP's transitive Payload-shape walk from descending into the internal buffer field. Walker sees the property typed as OwnedBytesHandle, finds the type is not forbidden, not Payload, not a value class — and stops.

OwnedBytesHandle is intentionally not a Payload itself — protocol- specific concerns (mqtt's PublishPayload, websocket's binary message type, etc.) supply their own thin wrapper that does the Payload marker duty. The companion codec OwnedBytesHandleCodec implements the canonical decode/encode flow that those wrappers' codecs delegate to.

Equality: every platform actual overrides equals / hashCode to delegate to handleEquals / handleHashCode (byte-content comparison). Two handles with the same bytes are ==, so data class containers that carry an OwnedBytesHandle field get structural equality "for free" without each declaring custom equals themselves.

JVM + Android actual for OwnedBytesHandle. See common kdoc for design rationale; both jvm and androidTarget source-sets dependsOn jvmCommonMain so this single file serves both.