Imagine I have a quantum circuit of n qubits and I want to measure the expected value of a single-qubit operator (let's say PauliZ) for each qubit. This is easily done in Pennylane with the following line:
return [qml.expval(qml.PauliZ(wires=i)) for i in range(n_qubits)]
Running this on real quantum hardware, how is this measurement done? Does it measure $H=ZIII...I$ first, $H=IZII...I$ afterwards and so forth, does it sample the circuit in computational basis and compute each qubit's expected value out of the odds, or it is something else?
Thank you in advance.