Function prepare 

pub fn prepare(
    connection: &Arc<Mutex<RawConnection<SyncStream>>>,
    query: &str,
    param_types: &[Oid],
) -> Result<PreparedStatement>

Prepares a statement using the extended query protocol.

Errors

• Returns Error (connection) if the connection mutex is poisoned.
• Returns Error (server) if the server rejects the Parse request (SQL syntax error, unknown parameter OIDs, etc.).
• Returns Error (I/O) / Error (closed) on wire-protocol I/O failure.