History of CasFs::readdir 1 change

In crates/flow-casfs/src/main.rs, lines 238–259 on ea81796bb757d87bf961a6e92044f84febf655d90b08c665c815d665fbaab873. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 238,259:crates/flow-casfs/src/main.rs.