qsimcirq performance overhead

[sergeisakov]

qsimcirq Python performance overhead is very high for small circuits. Say, for a 10-qubit circuit, it can be two orders of magnitude larger than the actual simulation time.

[95-martin-orion]

This profile graph is generated from a benchmark against 1000 circuits, each with 2 qubits and 4 gates. A notable culprit is the getattr method, which consumes ~10% of the runtime (compared to ~0.56% for the actual simulation)