Method null_read

cpp/src/arrow/util/rle_encoding_internal.h:869–869

  constexpr size_type null_count() const noexcept { return null_count_; }

  constexpr size_type null_read() const noexcept { return null_read_; }

  constexpr size_type null_remaining() const noexcept {
    ARROW_DCHECK_LE(null_read_, null_count_);