public class Tester
    {
        public const string TEXT_HEADER = "abc-test1";
        public const string PROC_HEADER = "prt-test2";
        // ... some more header keys

        public int TextId { get; set; }
        public int TextIdHeader { get; set; }

        public string ProcId { get; set; }
        public string ProcIdHeader { get; set; }

        public string DbId { get; set; }
        public string DbIdHeader { get; set; }

        public string ContextHeader { get; set; }
        public ContextStr ContextStr { get; set; }

        public string LocalHeader { get; set; }
        public LocalStr LocalStr { get; set; }

        public static string GenerateDbId() => GenerateId();
        public static string GenerateThetaId() => GenerateId();
        public static string GenerateProcId() => Guid.NewGuid().ToString();

        private static string GenerateId()
        {
            var data = Guid.NewGuid().ToByteArray();
            var byteData = BitConverter.ToUInt64(data, 0);
            return byteData.ToString();
        }

        public Tester() { }

        public Tester(IDictionary<string, StringValues> headers)
        {
          // exactly same content as I mentioned in my original answer
        }

        private string GetHeaderValue(IDictionary<string, StringValues> headers, string headerKey)
        {
            headers.TryGetValue(headerKey, out var headerValues);
            if (headerValues.Count > 0) return headerValues[0];
            return null;
        }
    }