code: def test_await_syntax():  # noqa
      L = []
  
      async def write(x):
          await asyncio.sleep(0.1)
          L.append(x)
  
      async def f():
          source = Stream(asynchronous=True)
          source.map(inc).buffer(3).sink(write)
  
          start = time()
          for x in range(6):
              await source.emit(x)
          stop = time()
  
          assert 0.2 < stop - start < 0.4
          assert 2 <= len(L) <= 4
  
      asyncio.run(f())
  
imports: import asyncio
  from time import time
  from distributed.utils_test import inc
  from streamz import Stream
label_desc: Use image node_id 1 for calling a global function with example usage: test_await_syntax() without return types