pub(crate) fn from_pool(
        connection: PoolConnection<Postgres>,
        tags: Option<ConnectionTags>,
        traced_connections: Option<&Arc<TracedConnections>>,
    ) -> Self {
        let created_at = Instant::now();
        let inner = ConnectionInner::Pooled(PooledConnection {
            connection,
            tags,
            created_at,
            traced: if let Some(connections) = traced_connections {
                let id = connections.acquire(tags, created_at);
                (Arc::downgrade(connections), id)
            } else {
                (Weak::new(), 0)
            },
        });
        Self {
            inner,
            _marker: PhantomData,
        }
    }
Creates a `Connection` using a pool of connections.
This method borrows one of the connections from the pool, and releases it
after `drop`.
core/lib/db_connection/src/connection.rs