Uploading files to sharepoint with RestSharp and their rest API is adding header and trailer lines to every file

I'm uploading to sharepoint using a c# client, and every file I Upload gets extra data included. A one line CSV file gets turned into a 7 line file that isn't usable. This is what my one line file upload turned into:

-----------AEE7A299-297A-41E0-B1CC-A72050FCDD28 
Content-Disposition: form-data; name="ControlFile_RCTI_statement_20220218_145832.csv"; filename="ControlFile_RCTI_statement_20220218_145832.csv"    
Content-Type: application/octet-stream  

File;Class;Account Number;Effective Date;Product;Account Type;Document Name 

-----------AEE7A299-297A-41E0-B1CC-A72050FCDD28--   

My upload code is using restSharp

public async Task UploadFile(string filePath, string list, string folderPath)
{
    await CheckTokenAsync();
    var fileName = Path.GetFileName(filePath);
    var endpoint = $"{spCredentials.sharepointSubSiteFullUrl}/_api/web/GetFolderByServerRelativeUrl('{list}/{folderPath}')/Files/Add(url='{fileName}', overwrite=false)";
    var client = new RestClient(endpoint);
    client.Timeout = 30000;
    var request = new RestRequest(Method.POST);
    request.AddHeader("Authorization", $"Bearer {token}");
    request.AddHeader("Accept", "application/json;odata=verbose");
    request.AddFile(fileName, filePath);
    var response = await client.ExecuteAsync(request);
    if (response.StatusCode == HttpStatusCode.OK)
    {
        var fileData = JsonConvert.DeserializeObject<SPSingleResultContainer>(response.Content);
        var link = fileData.d.__metadata.uri;
        await SendRequest<string>($"{link}/CheckIn()", Method.POST);
    }
    else
        throw new Exception($"Upload Failed with message: " + response.ErrorMessage);
}

I've also uploaded this question to SO at https://stackoverflow.com/questions/71168414/uploading-files-to-sharepoint-with-restsharp-and-their-rest-api-is-adding-header