159   // Concurrency + AbortSignal
165   }, 2), { signal: ac.signal, concurrency: 2, highWaterMark: 0 });  property
181   // Concurrency result order
185   }, { concurrency: 2 });  property
197   // highWaterMark with small concurrency
210   }, { concurrency: 2 });  property
220   // highWaterMark with a lot of items and large concurrency
257   }, { concurrency: 6 });  property
268   // Custom highWaterMark with a lot of items and large concurrency
305   }, { concurrency: 5, highWaterMark: 7 });  property
329       }, { concurrency: 2 })  property
348     concurrency: 'Foo'  property
351     concurrency: -1  property