Options for a ranged read. Provide start (with optional end), or
suffixBytes.
interface ReadRangeOptionsLast byte to return, inclusive. Clamped to EOF rather than rejected.
An ETag the caller already holds. An unchanged file answers with
unchanged: true and no bytes.
An ETag from an earlier chunk. The range is honored only while the file
still matches it.
First byte to return. With end, an inclusive range.
Return the last N bytes. Mutually exclusive with start/end.
Request timeout in seconds.