You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: get_more.rs
    path of file: ./repos/mongo-rust-driver/src/operation
    
    the code of the file until where you have to start completion: #[cfg(test)]
mod test;

use std::{collections::VecDeque, time::Duration};

use bson::{Document, RawDocumentBuf};
use serde::Deserialize;

use crate::{
    bson::{doc, Bson},
    change_stream::event::ResumeToken,
    cmap::{conn::PinnedConnectionHandle, Command, RawCommandResponse, StreamDescription},
    cursor::CursorInformation,
    error::{ErrorKind, Result},
    operation::OperationWithDefaults,
    options::SelectionCriteria,
    results::GetMoreResult,
    Namespace,
};

#[derive(Debug)]
pub(crate) struct GetMore<'conn> {
    ns: Namesp
    
    fn build(&mut self, _description: &StreamDescription) -> Result<Command> {
        let mut body = doc! {
            Self::NAME: self.cursor_id,
            "collection": self.ns.coll.clone(),
        };

        if let Some(batch_size) = self.batch_size {
            if batch_size > std::i32::MAX as u32 {
                return Err(ErrorKind::InvalidArgument {
                    message: "The batch size must fit into a signed 32-bit integer".to_string(),
                }
                .into());
            } else if batch_size != 0 {
                body.insert("batchSize", batch_size);
            }
        }

        if let Some(ref max_time) = self.max_time {
            body.insert("maxTimeMS", max_time.as_millis() as i32);
        }

        if let Some(ref comment) = self.comment {
            body.insert("comment", comment);
        }

        Ok(Command::new(
            Self::NAME.to_string(),
            self.ns.db.clone(),
            body,
        ))
    }