[#24] Client: Implement pool part1

first iteration - base classes and methods

Signed-off-by: Pavel Gross <p.gross@yadro.com>

src/FrostFS.SDK.ClientV2/Poll/MethodStatus.cs

@@ -0,0 +1,19 @@
+namespace FrostFS.SDK.ClientV2;
+
+public class MethodStatus(string name)
+{
+    private readonly object _lock = new();
+
+    public string Name { get; } = name;
+
+    public StatusSnapshot Snapshot { get; set; } = new StatusSnapshot();
+
+    internal void IncRequests(ulong elapsed)
+    {
+        lock (_lock)
+        {
+            Snapshot.AllTime += elapsed;
+            Snapshot.AllRequests++;
+        }
+    }
+}