The empty thread id a composer's sub-screen edges carry. The composer has no
thread, and an edge's step cannot fail, so the step hands the only value it
has and the sub-screen's enter refuses it before any request or navigation.
The Direct screens' own sentinel; no published declaration names it.
The empty thread id a composer's sub-screen edges carry. The composer has no thread, and an edge's step cannot fail, so the step hands the only value it has and the sub-screen's enter refuses it before any request or navigation.
The Direct screens' own sentinel; no published declaration names it.