title: AFNetworking accept all content types
body: <p>I am doing a request operation to download every types of files from a server with AFHTTPRequestOperationManager.</p>
  
  <p>At the moment, I am doing like this:</p>
  
  <pre><code>AFHTTPRequestOperationManager *manager = [[AFHTTPRequestOperationManager alloc] initWithBaseURL:baseURL];
  manager.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"image/jpeg", @"image/gif", @"image/png", @"application/pdf", ..., nil];
  </code></pre>
  
  <p>It is working nicely, but I would like to enable all content types possible to avoid missing some.</p>
  
  <p>Is it possible to initiate the acceptable content types for every kind of existing content? Something like:</p>
  
  <pre><code>manager.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"*", nil];
  </code></pre>
  
  <p>Thank you.</p>