TypedL2capChannel
A typed, framed view over an L2capChannel.
Wraps an accepted L2CAP channel together with a BleCodec and a Framer so that callers read and write typed values directly. Pairs with L2capListener.framedConnections: the listener accepts raw channels and each accepted channel is wrapped into a TypedL2capChannel.
The underlying channel is intentionally not exposed. Collecting raw bytes from it alongside incoming would split the byte stream between two collectors and corrupt frames; writing raw bytes would bypass the framer and produce a stream the peer cannot decode. Use a separate L2capListener.incoming collection if raw access is required.
mtu, psm, and isOpen forward to the underlying channel for convenience. close closes the underlying channel.