This crate defines ReadAt, WriteAt, and EditAt traits which define
interfaces to random-access or seekable devices, such as normal files, block
devices, disk partitions, and memory buffers.
It also defines RangeReader, RangeWriter, and RangeEditor types which
implement the above traits and and can be constructed from any file-like type.
On Posix-ish platforms, with support for WASI in development, these types just
contain a single file descriptor (and implement AsRawFd), plus any
resources needed to safely hold the file descriptor live. On Windows, they
contain a single file handle (and implement AsRawHandle).