# Varint

`Varint` is represented as `value::CqlVarint` or [`num_bigint::BigInt`](https://docs.rs/num-bigint/0.4.0/num_bigint/struct.BigInt.html).

## num_bigint::BigInt

To make use of `num_bigint::BigInt` type, user should enable one of the available feature flags (`num-bigint-03` or `num-bigint-04`). They enable support for `num_bigint::BigInt` v0.3 and v0.4 accordingly.

## value::CqlVarint

Without any feature flags, the user can interact with `Varint` type by making use of `value::CqlVarint` or `value::CqlVarintBorrowed` which are very simple wrappers representing the value as signed binary number in big-endian order.

## Example

```rust
use futures::TryStreamExt;
use num_bigint::BigInt;
use std::str::FromStr;

// Insert a varint into the table
let to_insert: BigInt = BigInt::from_str("12345")?;
session
    .query_unpaged("INSERT INTO keyspace.table (a) VALUES(?)", (to_insert,))
    .await?;

// Read a varint from the table
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
    .await?
    .rows_stream::<(BigInt,)>()?;
while let Some((varint_value,)) = iter.try_next().await? {
    println!("{:?}", varint_value);
}
```