is_pull: bool,

                    if is_tag {
                        Ok(CS::State(
                            txn.state_from_prefix(&*current_channel.read(), h)?.0,
                        ))

                    if is_pull {
                        if is_tag {
                            Ok(CS::State(
                                txn.state_from_prefix(&remote_ref.lock().states, h)?.0,
                            ))
                        } else {
                            Ok(CS::Change(txn.hash_from_prefix_remote(&remote_ref, h)?))
                        }

                        Ok(CS::Change(txn.hash_from_prefix(h)?.0))

                        if is_tag {
                            Ok(CS::State(
                                txn.state_from_prefix(&current_channel.read().states, h)?.0,
                            ))
                        } else {
                            Ok(CS::Change(txn.hash_from_prefix(h)?.0))
                        }

                false,

                true,

        channel: &Self::Channel,

        channel: &Self::States,

        for x in btree::iter(&self.txn, &channel.states, Some((&h, None)))

        for x in btree::iter(&self.txn, &channel, Some((&h, None)))

        channel: &Self::Channel,

        channel: &Self::States,

    #[error("while retrieving {:?}: {}", hash, err)]
    IoHash {
        err: std::io::Error,
        hash: crate::pristine::Hash,
    },

        let mut r = std::fs::File::open(file)?;

        let mut r = std::fs::File::open(file).map_err(|err| if let Some(h) = hash {
            ChangeError::IoHash {
                err,
                hash: *h,
            }
        } else {
            ChangeError::Io(err)
        })?;

        let mut r = std::fs::File::open(path)?;

        let mut r = std::fs::File::open(path).map_err(|err| ChangeError::IoHash {
            err,
            hash,
        })?;