Trying to do so involves using the weird syntax of GetAwaiter().GetResult().

Beside that fact, it works; but does it sucks to do so? If yes, then why?

Original:

internal static ISector Read(ISector sector, Stream stream)
{
    using var scope = new ArrayPoolScope<byte>(GetLength(sector));

    stream.ReadExactly(scope.Span);

    var result = Read(sector, scope.Span);

    return result;
}

internal static async Task<ISector> ReadAsync(ISector sector, Stream stream)
{
    using var scope = new ArrayPoolScope<byte>(GetLength(sector));

    await stream.ReadExactlyAsync(scope.Memory);

    var result = Read(sector, scope.Span);

    return result;
}

Modified:

internal static ISector Read(ISector sector, Stream stream)
{
    var result = ReadAsync(sector, stream).GetAwaiter().GetResult();

    return result;
}

internal static async Task<ISector> ReadAsync(ISector sector, Stream stream)
{
    using var scope = new ArrayPoolScope<byte>(GetLength(sector));

    await stream.ReadExactlyAsync(scope.Memory);

    var result = Read(sector, scope.Span);

    return result;
}