Expand description
Bounds-checked little-endian readers (the Paranoid Gatekeeper standard).
btrfs is little-endian on disk throughout. Every reader yields 0 when the
requested range lies outside the buffer, so a malformed or truncated image
can never panic a parser. Callers that need to distinguish “field absent”
from “field is zero” bounds-check the buffer length up front and surface
crate::BtrfsError::Truncated.