wip: add close method to aggregator

src/aggregator.rs

@@ -13,6 +13,12 @@ pub trait Aggregator<Candle, T: TakerTrade> {
     /// Some output only when a new candle has been created,
     /// otherwise it returns None
     fn update(&mut self, trade: &T) -> Option<Candle>;
+
+    /// Close current active candle and return it
+    /// 
+    /// # Returns:
+    /// Last active candle, or None if candle was already finalized
+    fn close(&mut self) -> Option<Candle>;
 }
 
 /// An `Aggregator` that is generic over
@@ -66,6 +72,15 @@ where
         }
         None
     }
+
+    fn close(&mut self) -> Option<C> {
+        if !self.candle.finalized() {
+            self.candle.finalize();
+            return Some(self.candle.clone());
+        }
+
+        None
+    }
 }
 
 #[cfg(test)]