old_contents: import asyncio
  
  from simple_rest_client.api import API
  from simple_rest_client.resource import AsyncResource
  
  
  class FileUploadResource(AsyncResource):
      actions = {
          'create': {'method': 'POST', 'url': 'post.php?dir=example'},
      }
  
  
  # http://blog.henrycipolla.com/2011/12/testing-multipartform-data-uploads-with-post-test-server/
  files = {'file': open('github.py', 'rb')}
  post_test_server_api = API(api_root_url='http://posttestserver.com/', timeout=10)
  post_test_server_api.add_resource(resource_name='file_upload', resource_class=FileUploadResource)
  
  
  async def main():
      response = await post_test_server_api.file_upload.create(body=files)
      print('httpbin_api.basic_auth.retrieve={!r}'.format(response.body))
  
  loop = asyncio.get_event_loop()
  loop.run_until_complete(main())
  
new_contents: import asyncio
  
  from simple_rest_client.api import API
  from simple_rest_client.resource import AsyncResource
  
  
  class FileUploadResource(AsyncResource):
      actions = {
          'create': {'method': 'POST', 'url': 'post.php?dir=example'},
      }
  
  
  # http://blog.henrycipolla.com/2011/12/testing-multipartform-data-uploads-with-post-test-server/
  files = {'file': open('github.py', 'rb')}
  post_test_server_api = API(api_root_url='http://posttestserver.com/', timeout=10)
  post_test_server_api.add_resource(resource_name='file_upload', resource_class=FileUploadResource)
  
  
  async def main():
      response = await post_test_server_api.file_upload.create(body=files)
      print('post_test_server_api.file_upload.create={!r}'.format(response.body))
  
  loop = asyncio.get_event_loop()
  loop.run_until_complete(main())
  
subject: Fix async_file_upload example