Stream BufRead decompressor does not consume all the compressed bytes

[Ten0]

Stream BufRead decompressor does not consume all the compressed bytes, despite reading all the decompressed bytes and calling finish().
This is an issue when doing block compression/decompression.
No other decompressor I have tested seems to have this behavior (deflate with flate2, bzip2 with bzip2, xz with xz2).

Reproduction

The last assert fails:

fn main() {
	let to_compress = &[54, 6, 102, 111, 111, 84, 6, 98, 97, 114];
	let mut encoder = zstd::stream::write::Encoder::new(Vec::new(), 0).unwrap();
	std::io::Write::write_all(&mut encoder, to_compress).unwrap();
	let buf = encoder.finish().unwrap();
	assert_eq!(
		buf,
		&[40, 181, 47, 253, 0, 88, 81, 0, 0, 54, 6, 102, 111, 111, 84, 6, 98, 97, 114]
	);

	let mut decoder = zstd::stream::read::Decoder::with_buffer(buf.as_slice()).unwrap();
	let mut decompressed = Vec::new();
	let mut buf = [0u8; 1];
	for _ in 0..to_compress.len() {
		assert_eq!(std::io::Read::read(&mut decoder, &mut buf).unwrap(), 1);
		decompressed.extend_from_slice(&buf);
	}
	assert_eq!(decompressed, to_compress);

	let reader_after_decompression = decoder.finish();
	dbg!(&reader_after_decompression);
	assert_eq!(reader_after_decompression, &[]); // Panics: `reader_after_decompression` is `&[114]` now.
}

Meaning that the reader hasn't actually consumed all the bytes of the compressed input, despite all decompressed output being properly decompressed and read and finish being called.

Note that this is specific to the scenario where it's the reader stopping to ask for bytes.

(zstd 0.13)