/// This module defines the `CascSpanHeader` struct, which represents the header for a span of data
/// in a CASC archive. The header contains metadata such as encoding key, content size, flags,
/// hash, and checksum.
/// Represents the header for a span of data in a CASC archive.
///
/// The `CascSpanHeader` contains metadata fields used to identify and validate a span of file data.
pub