Graph: downloading a text file throws exception

Question

I am trying to download a simple text file from OneDrive:

// get the DriveItem for 'test.txt' (Id = T_ID)
var file = await graphClient.Drives["me"].Items[T_ID].GetAsync();                                 
Debug.Assert(file != null && file.File != null);
sb.Append(file.Name?.ToString());
sb.AppendLine("  Last modified: " + file.LastModifiedDateTime.ToString());
// download and display content
sb.AppendLine("File content:\n");
var stream = await graphClient.Drives["me"].Items[T_ID]
                              .Content
                              .GetAsync();
if (stream == null) sb.AppendLine("Stream is null");
else 
{
    try
    {
        using var reader = new StreamReader(stream);
        sb.AppendLine($"{reader.ReadToEnd()}");
    }
    catch (Exception ex)
    {
        sb.AppendLine($"{ex.Message}");
    }
} 

'test.txt' simply contains the string "This is a test document", T_ID is its Id in the Drive.

I get:

Exception of type 'Android.OS.NetworkOnMainThread Exception' was thrown

I tried to modify the Android manifest including android:usesCleartextTraffic="true" - same result.

Notes:

1. In Windows machine it works without any problem
2. Uploading the same file does not throw any exception.

Answer 1

The stream returned by Graph must be copied to a local stream:

                                    var memstrem = new MemoryStream();
                                    stream.CopyTo(memstrem);
                                    memstrem.Position = 0;
                                    using var reader = new StreamReader(memstrem);
                                    sb.AppendLine(reader.ReadToEnd());