Feat(find): add anyAsync()

- to apply issue #3

src/MongoSharpen/Builders/Find.cs

@@ -101,6 +101,15 @@ public Task<List<T>> ManyAsync(Expression<Func<T, bool>> expression, Cancellatio
         _filters = Builders<T>.Filter.Empty.Match(expression);
         return ExecuteAsync(cancellation);
     }
+
+    public async Task<bool> AnyAsync(CancellationToken cancellation = default)
+    {
+        Limit(1); //to prevent fetching more documents than needed
+
+        using var cursor = await ExecuteCursorAsync(cancellation).ConfigureAwait(false);
+        await cursor.MoveNextAsync(cancellation).ConfigureAwait(false);
+        return cursor.Current.Any();
+    }
 }
 
 public sealed class Find<T, TProjection> where T : IEntity

tests/MongoSharpen.Test/DbContexts/DbContextTests.Find.cs

@@ -148,6 +148,26 @@ public async Task
         result.Count.Should().Be(1);
     }
 
+    [Fact]
+    public async Task find__on_execute_any__when_found__should_return_true()
+    {
+        var first = _bookFixture.Books.First();
+
+        var ctx = DbFactory.Get("library");
+        var result = await ctx.Find<Book>(x => x.MatchId(first.Id)).AnyAsync();
+
+        result.Should().BeTrue();
+    }
+
+    [Fact]
+    public async Task find__on_execute_any__when_not_found__should_return_false()
+    {
+        var ctx = DbFactory.Get("library");
+        var result = await ctx.Find<Book>(x => x.MatchId(Guid.NewGuid().ToString())).AnyAsync();
+
+        result.Should().BeFalse();
+    }
+
     [Fact]
     public async Task find__with_projection__when_no_filters__should_get_all()
     {