Function atomic_request 

pub fn atomic_request(
    prefix: Vec<Statement>,
    quads: &EncodedQuads,
    suffix: Vec<Statement>,
    caps: &Capabilities,
) -> Result<Request, usize>

One atomic request: prefix, the inserts of quads, then suffix. Atomicity forbids splitting it, so Err(n) reports its n statements when they exceed the backend’s per-request limit (each statement is already below the SQL-length limit).