Emit a simple "new candle" message to allow UI's to refresh charts

freqtrade/data/dataprovider.py

@@ -101,16 +101,13 @@ class DataProvider:
         """
         return self.__producer_pairs.get(producer_name, []).copy()
 
-    def _emit_df(
-        self,
-        pair_key: PairWithTimeframe,
-        dataframe: DataFrame
-    ) -> None:
+    def _emit_df(self, pair_key: PairWithTimeframe, dataframe: DataFrame, new_candle: bool) -> None:
         """
         Send this dataframe as an ANALYZED_DF message to RPC
 
         :param pair_key: PairWithTimeframe tuple
-        :param data: Tuple containing the DataFrame and the datetime it was cached
+        :param dataframe: Dataframe to emit
+        :param new_candle: This is a new candle
         """
         if self.__rpc:
             self.__rpc.send_msg(
@@ -123,6 +120,15 @@ class DataProvider:
                     }
                 }
             )
+            if new_candle:
+                self.__rpc.send_msg(
+                    {
+                        'type': RPCMessageType.NEW_CANDLE,
+                        'data': {
+                            'key': pair_key,
+                            }
+                        }
+                    )
 
     def _add_external_df(
         self,