add failing test case for memory leak

tests/codex/utils/asyncprofiler/testasyncprofiler.nim

@@ -0,0 +1,31 @@
+import pkg/asynctest
+import pkg/chronos
+
+import pkg/codex/utils/asyncprofiler
+
+type
+  FakeFuture = object
+    id: uint
+    internalLocation*: array[LocationKind, ptr SrcLoc]
+
+
+suite "asyncprofiler":
+
+  test "should not keep metrics for a pending future in memory after it completes":
+
+    var fakeLoc =  SrcLoc(procedure: "foo", file: "foo.nim", line: 1)
+    let future = FakeFuture(
+      id: 1,
+      internalLocation:  [
+      LocationKind.Create: addr fakeLoc,
+      LocationKind.Finish: addr fakeLoc,
+    ])
+
+    var profiler = AsyncProfiler[FakeFuture]()
+
+    profiler.handleFutureCreate(future)
+    profiler.handleFutureComplete(future)
+
+    check len(profiler.getPerFutureMetrics()) == 0
+
+