//! Low-level access to reading and writing chunk file based formats.//!//! See the [git documentation](https://github.com/git/git/blob/seen/Documentation/technical/chunk-format.txt) for details.#![deny(unsafe_code)]#![deny(rust_2018_idioms, missing_docs)] use std::convert::TryInto;use std::ops::Range; /// An identifier to describe the kind of chunk, unique within a chunk file, typically in ASCIIpub type Kind = [u8; 4]; /// A special value denoting the end of the chunk file table of contents.pub const SENTINEL: Kind = [0u8; 4]; /// Turn a u64 Range into a usize range safely, to make chunk ranges useful in memory mapped files.pub fn into_usize_range(Range { start, end }: Range<file::Offset>) -> Option<Range<usize>> {    let start = start.try_into().ok()?;    let end = end.try_into().ok()?;    Some(Range { start, end })} ///pub mod file;