Mirror of the FrameSink concrete migrations slice (760e40b) on the
read side. DiscStream is the only meaningful source impl in tree;
all the mux/* impls are sinks.
The round-1 blanket impl<T: Stream + Send> FrameSource for T
already covers DiscStream if it's Send. This slice:
- Audits DiscStream's interior types for Send (its Box<dyn
SectorReader> already requires Send via the trait's super-bound;
verify nothing else interior breaks Send).
- Adds a synthetic-input test that constructs Box<dyn FrameSource>
over a DiscStream, reads frames through the trait object, and
exercises info() / headers_ready() / codec_private().
- (Conditional) Adds a direct FrameSource impl on DiscStream only
if call-site ergonomics demand it; otherwise relies on the
blanket.
No caller migrated. mux::resolve::input still returns
Box<dyn Stream>; autorip / CLI consumers still call Stream::read.
Per-caller migration is a later slice.
See freemkv-private/memory/0_18_redesign.md.
Single contributor: MattJackson.
matthew
356380f66a