FileSystemwatcher with Documents Indexing as Attachments (c#,Nest)

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Hi All,
I'm trying to reproduce a console application which watches a folder and any new additions of documents to the folder are to be Indexed to ES .

It is working fine If I move/add 3-4 documents at a time and able to index. But if I move around 30 documents at a time, It is not indexing all the documents, instead indexing only one. But If I run the code with break points , then even 30 documents are also getting indexed.
Can some one help me in solving this.

 static void OnCreated(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine("File Created: Path: {0}, \n Name: {1}", e.FullPath, e.Name);
            Indexdoc(e.FullPath);
        }

If I dont call the Indexdoc(e.FullPath) method in the above code and instead print the changes, it is showing all the filenames added perfectly. so there is no problem with the filesystemwatcher. I think indexing documents is taking time to generate response and come back to onCreated method.

public static void Indexdoc(string newFilePath)
        {
            List<Document> list = new List<Document>(); //list of Document class objects
            List<string> filesList = new List<string>(); //list of files in the path received on method call
            string path = string.Empty;

            client = ConfigSettings.connection();
			
            if (newFilePath == null) //for FULL Indexing
            {
               //some code here
            }
            else //for new files indexing
            {
                filesList.Add(newFilePath); //adds only one file everytime the method is called.
                //the newFilePath will be of type C:/Documents/abc.txt
            }

            try
            {
                foreach (string file in filesList)
                {
                    Attachment attach = new Attachment
                    {
                        Name = Path.GetFileNameWithoutExtension(file),
                        Content = Convert.ToBase64String(File.ReadAllBytes(file)),
                        ContentType = Path.GetExtension(file)
                    };

                    var doc = new Document()
                    {
                        Title = Path.GetFileNameWithoutExtension(file),
                        FilePath = Path.GetFullPath(file), //added to get the path of the file
                        File = attach
                    };

                    list.Add(doc);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message.ToString());
            }
            
			var response = client.IndexMany(list, "trial");
		}

Can some one help me in solving this.

TIA