BitIterator panics when retrieving length

[Jefffrey]

Describe the bug

BitIterator panics when retrieving its length via ExactSizeIterator

To Reproduce

    #[test]
    fn test123() {
        let b = BitIterator::new(&[0b00000010], 0, 2);
        dbg!(b.len());
    }

Output:

arrow-rs$ cargo test -p arrow-buffer --lib util::bit_iterator::tests::test123 -- --nocapture
    Blocking waiting for file lock on build directory
   Compiling arrow-buffer v53.0.0 (/home/jeffrey/Code/arrow-rs/arrow-buffer)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 9.48s
     Running unittests src/lib.rs (/media/jeffrey/1tb_860evo_ssd/.cargo_target_cache/debug/deps/arrow_buffer-9f4040912c29ccf9)

running 1 test
thread 'util::bit_iterator::tests::test123' panicked at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/iter/traits/exact_size.rs:122:9:
assertion `left == right` failed
  left: None
 right: Some(0)
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
test util::bit_iterator::tests::test123 ... FAILED

failures:

failures:
    util::bit_iterator::tests::test123

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 128 filtered out; finished in 0.00s

error: test failed, to rerun pass `-p arrow-buffer --lib`

Expected behavior

Doesn't panic

Additional context

Panic is here: https://github.com/rust-lang/rust/blob/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/iter/traits/exact_size.rs#L122

Looks like BitIterator implements ExactSizeIterator:

arrow-rs/arrow-buffer/src/util/bit_iterator.rs

Line 71 in f41c258

impl<'a> ExactSizeIterator for BitIterator<'a> {}

But it does not override the default size_hint from Iterator:

arrow-rs/arrow-buffer/src/util/bit_iterator.rs

Lines 56 to 69 in f41c258

	impl<'a> Iterator for BitIterator<'a> {
	type Item = bool;
	fn next(&mut self) -> Option<Self::Item> {
	if self.current_offset == self.end_offset {
	return None;
	}
	// Safety:
	// offsets in bounds
	let v = unsafe { get_bit_raw(self.buffer.as_ptr(), self.current_offset) };
	self.current_offset += 1;
	Some(v)
	}
	}

According to docs: https://doc.rust-lang.org/std/iter/trait.ExactSizeIterator.html

When doing so, the implementation of [Iterator::size_hint] must return the exact size of the iterator.

[Beihao-Zhou]

take

[alamb]

label_issue.py automatically added labels {'arrow'} from #6495