Using CsvHelper with a Stream

I'm trying to use CsvHelper to read in a CSV file and create a DataTable from it. The first row will be a header record providing column names, but other than that, the structure of the file is unknown. If I use the following code (taken from an example by the author of CsvHelper), it works.

using (var reader = new StreamReader("path\\to\\file.csv"))
using (var csv = new CsvReader(reader))
{
    // Do any configuration to `CsvReader` before creating CsvDataReader.
    using (var dr = new CsvDataReader(csv))
    {        
        var dt = new DataTable();
        dt.Load(dr);
    }
}

However, if I use an alternate constructor for the StreamReader that takes a Stream as a parameter instead of a file path, then the creation of the CsvDataReader fails with an error message of "Synchronous reads are not supported."

I've tried a few other methods of CsvHelper in attempts to handle the data differently, but I keep running into the same error any time that the StreamReader is created by passing in a Stream rather than a file path. I'm starting to wonder whether the real issue lies with the implementation of StreamReader or with CsvHelper. Passing in a Stream makes much more sense in my situation (a Blazor Server app). Any ideas?

EDIT:

I believe David Specht is correct in that there is something unique about the particular stream I was using. In further testing, I've found that some strings do work. In the situation where I have the error, I am reading the stream from Steve Sanderson's BlazorInputFile component (on GitHub) using the IFileListEntry.Data stream interface. I suspect that there is something in its implementation that causes the error I'm getting. If that's the case, then a workaround would be helpful. (Maybe creating one stream from another to switch between asynchronous and synchronous streams? Not sure how to do that yet, but I'm going to give it a shot.)

As David Specht pointed out in his answer, and as indicated in my edit to the original question, it does work with some Streams. Something in the implementation of the stream, file.Data, in the example below doesn't work well with CsvHelper, causing the "Synchronous reads are not supported" error. This particular stream is an instance IFileListEntry.Data from the BlazorInputFile component created by Steve Sanderson and available on GitHub. (All in all, this component seems to work quite well keeping in mind that I'm using version 0.1.0-preview-00002 so thanks, Steve!)

By copying the stream to a new stream using Stream.CopyToAsync() the problem goes away. One caveat to keep in mind is that, after this function executes, both the input and output streams will be positioned at the end of the stream. The stream that will be used to create the CsvReader must be set back to the beginning in order for the CsvDataReader constructor to work properly. If this is not done, there will be a "No header record was found" error.

The following example works for me and will hopefully help someone else!

using (var stream2 = new MemoryStream())
{
    await file.Data.CopyToAsync(stream2);   // although file.Data is itself a stream, using it directly causes "synchronous reads are not supported" errors below.
    stream2.Seek(0, SeekOrigin.Begin);      // at the end of the copy method, we are at the end of both the input and output stream and need to reset the one we want to work with.
    var reader = new System.IO.StreamReader(stream2);

    using (var csv = new CsvReader(reader))
    {
        using (var dr = new CsvDataReader(csv)) // error happens here when "file.Data" is used as the stream: "Synchronous reads are not supported"
                                                // error happens here when the stream isn't reset to the beginning: "No header record was found"
        {
            var dt = new DataTable();
            dt.Load(dr);
        }
    }
}