finish receive udp data handle function

server/src/UdpServer.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Net.Sockets;
 using System.Text;
+using DotNext;
 
 public struct UDPData
 {
@@ -18,7 +19,8 @@ public class UDPServer
     private int listenPort;
     private UdpClient listener;
     private IPEndPoint groupEP;
-    private Dictionary<string, UDPData> udpData = new Dictionary<string, UDPData>();
+    private Dictionary<string, List<UDPData>> udpData = new Dictionary<string, List<UDPData>>();
+    private Mutex mutUdpData = new Mutex();
 
     /// <summary>
     /// Construct a udp server with fixed port
@@ -44,6 +46,84 @@ public class UDPServer
         }
     }
 
+    /// <summary>
+    /// Find UDP Receive Data According to ip address
+    /// </summary>
+    /// <param name="ipAddr"> IP Address</param>
+    /// <returns>UDP Data</returns>
+    public Optional<UDPData> FindData(string ipAddr)
+    {
+        UDPData? data = null;
+        try
+        {
+            var isOverTime = !mutUdpData.WaitOne(1000);
+            if (isOverTime) return Optional.None<UDPData>();
+            // Get
+            var listData = udpData[ipAddr];
+            data = listData[0];
+
+            // Delete
+            listData.RemoveAt(0);
+        }
+        catch
+        {
+            data = null;
+        }
+        finally
+        {
+            mutUdpData.ReleaseMutex();
+        }
+
+        // Return
+        if (data is null)
+        {
+            return Optional.None<UDPData>();
+        }
+        else
+        {
+            return Optional.Some((UDPData)data);
+        }
+    }
+
+    /// <summary>
+    /// Find UDP Receive Data Async
+    /// </summary>
+    /// <param name="ipAddr">[TODO:parameter]</param>
+    /// <param name="timeout">[TODO:parameter]</param>
+    /// <returns>[TODO:return]</returns>
+    public async ValueTask<Optional<UDPData>> FindDataAsync(string ipAddr, int timeout = 1000)
+    {
+        var time = 0;
+        UDPData? data = null;
+        while (time < timeout)
+        {
+            await Task.Delay(1);
+            try
+            {
+                var isOverTime = !mutUdpData.WaitOne(timeout - time);
+                if (isOverTime) break;
+                // Get
+                var listData = udpData[ipAddr];
+                data = listData[0];
+
+                // Delete
+                listData.RemoveAt(0);
+            }
+            catch
+            {
+                data = null;
+            }
+            finally
+            {
+                mutUdpData.ReleaseMutex();
+            }
+            if (data is null) continue;
+            else break;
+        }
+        if ((time >= timeout) || (data is null)) { return Optional.None<UDPData>(); }
+        else { return Optional.Some((UDPData)data); }
+    }
+
     private void ReceiveHandler(IAsyncResult res)
     {
         var remoteEP = new IPEndPoint(IPAddress.Any, listenPort);
@@ -57,13 +137,27 @@ public class UDPServer
             var remoteAddress = remoteEP.Address.ToString();
             var remotePort = remoteEP.Port;
             // Record UDP Receive Data
-            udpData.Add(remoteAddress, new UDPData()
+            if (udpData.ContainsKey(remoteAddress))
             {
-                addr = remoteAddress,
-                port = remotePort,
-                data = bytes,
-                datetime = nowtime,
-            });
+                var listData = udpData[remoteAddress];
+                listData.Add(new UDPData()
+                {
+                    addr = remoteAddress,
+                    port = remotePort,
+                    data = bytes,
+                    datetime = nowtime,
+                });
+            }
+            else
+            {
+                udpData.Add(remoteAddress, new List<UDPData>([new UDPData(){
+                    addr = remoteAddress,
+                    port = remotePort,
+                    data = bytes,
+                    datetime = nowtime,
+                }]));
+            }
+
             remoteStr = $"{remoteAddress}:{remotePort}";
         }
         else