C#

string listTitle = "TripLegs" ;

string listDescription = "This is a new list created using CSOM";
Microsoft.SharePoint.Client.List? newList = null;

using (var authenticationManager = new AuthenticationManager())
using (var context = authenticationManager.GetContext(site, user, password))
{
    context.Load(context.Web, p => p.Title);
    await context.ExecuteQueryAsync();
    Console.WriteLine($"Title: {context.Web.Title}");
    Web web = context.Web;

    // Create a new list
    ListCreationInformation creationInfo = new ListCreationInformation();
    creationInfo.Title = listTitle;
    creationInfo.Description = listDescription;
    creationInfo.TemplateType = (int)ListTemplateType.GenericList;
    newList = web.Lists.Add(creationInfo);

                    try
                    {
                        // Load the list and execute the query
                        context.Load(newList);
                        context.ExecuteQuery();

                        Console.WriteLine("List created successfully!");


                        FieldCollection fields = newList.Fields;

                        // set up the columns
                        #region ColumnHeaders
<pre>                        FieldCreationInformation fieldInfo_1 = new FieldCreationInformation(FieldType.Number)
                        {
                            DisplayName = "TripId",
                            InternalName = "TripId",
                            Group = "Custom Columns",
                            AddToDefaultView = true
                        };
                        // Create the field schema XML
                        string fieldSchema_1 = $"<Field Type='{fieldInfo_1.FieldType}' Name='{fieldInfo_1.InternalName}' DisplayName='{fieldInfo_1.DisplayName}' Group='{fieldInfo_1.Group}' />";
                        Field Field_1 = newList.Fields.AddFieldAsXml(fieldSchema_1, true, AddFieldOptions.DefaultValue);
                        Field_1.Update();
                        context.ExecuteQuery();

}
catch (Exception ex)
{
    // it already exists so instead of adding it, get it

Legs singleTripLeg = JsonSerializer.Deserialize<Legs>(inputLegsJSON);

// this is where we load the SharePoint List from a Record

// Create a new list item
ListItemCreationInformation itemCreateInfo = new ListItemCreationInformation();

Microsoft.SharePoint.Client.ListItem newItem = newList.AddItem(itemCreateInfo);

newItem["TripId"] = singleTripLeg.TripId;
// OK
newItem["ExternalReference"] = singleTripLeg.ExternalReference;
newItem["DepartureAirportId"] = singleTripLeg.DepartureAirportId;
newItem["ArrivalAirportId"] = singleTripLeg.ArrivalAirportId;
newItem["LandedLocal"] = singleTripLeg.LandedLocal;

newItem["LandedPinned"] = singleTripLeg.LandedPinned;


// if all goes well, then we update

newItem.Update();

// if all goes well, then we exccute query

context.ExecuteQuery();

1. The await operator here does not appear to affect the locking behaviour. It's only waiting for the Task.Run to complete.
2. Inside the Task.Run, we have a lock statement. You can think of this as running on a different thread from the caller.
3. Each call to this method will create a new task, which will attempt to acquire the lock independently.

private static readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);

internal static async Task Lock<T>(this T lockObject, Action DoAction) where T : class
{
  try
  {
    await _semaphore.WaitAsync();
    DoAction();
  }
  finally
  {
    _semaphore.Release();
  }
}

public async Task<short[]> GetSamples()
{
    if (!ContainsAudio()) 
        throw new ArgumentException(nameof(G711.Alaw));
    short[] samples = [];
    NativePointer pointer = _nativePointer!;
    await pointer.Lock(() =>
    {
        unsafe
        {
            var sampleCount = pointer.Size >> 1;
            samples = new short[sampleCount];
            var memoryBlock = pointer.GetMemoryBlock();
            var value = (short*)memoryBlock;
            for (var i = 0; i < sampleCount; i++)
            {
                samples[i] = *value++;
            }
        }
    });
    return samples;
}

FileStream fs = new System.IO.FileStream(img_path, FileMode.Open, FileAccess.Read);
img = Image.FromStream(fs);

Image imgThumb = img.GetThumbnailImage(thumbnailSize.Width, thumbnailSize.Height, null, IntPtr.Zero);
//imgThumb use it for thumbnail

fs.Close();
fs.Dispose();

img.Dispose();