仅当插入断点时，异步代码才似乎有效

Question

I have the following C# code:

var response = client.GetAsync(uri).Result;
MemoryStream stream = new MemoryStream();
response.Content.CopyToAsync(stream);
System.Console.WriteLine(stream.Length);

When I insert a breakpoint before the first statement and then continue the program, the code works fine and over 4 MB of data gets stored in the stream.

But if I run the program without any breakpoints or inserting the breakpoint after the after the first statement shown above, the code runs but no data or only 4 KB of data gets stored in the stream.

Can someone please explain why this is happening?

Edit: Here is what I am trying to do in my program. I use couple of HttpClient.PostAsync requests to get a uri to download a wav file. Then I want to download the wav file into a memory stream. I don't know of any other ways to do this yet.

Answer 1

It seems like you are basically messing the flow of async and await .

The async call will be waited to complete and recapture the task when you use await keyword.

The mentioned code does not clarify whether you are using the async signature in your method or not. Let me clarify the solution for you

Possible solution 1:

public async Task XYZFunction()
{
  var response = await client.GetAsync(uri); //we are waiting for the request to be completed
  MemoryStream stream = new MemoryStream();
  await response.Content.CopyToAsync(stream); //The call will wait until the request is completed
  System.Console.WriteLine(stream.Length);
} 

Possible solution 2:

public void XYZFunction()
{
  var response = client.GetAsync(uri).Result; //we are running the awaitable task to complete and share the result with us first. It is a blocking call
  MemoryStream stream = new MemoryStream();
  response.Content.CopyToAsync(stream).Result; //same goes here
  System.Console.WriteLine(stream.Length);
}