Improve serialization for jsonl format

 * Imrpove logic for text and html tracking
 * Fix regressions

traceml/traceml/events/schemas.py

@@ -348,6 +348,23 @@ def get_value(self, dump=True):
         if self.dataframe is not None:
             return self.dataframe.to_json() if dump else self.dataframe
 
+    def to_json(
+        self,
+        humanize_values: bool = False,
+        include_kind: bool = False,
+        include_version: bool = False,
+        kind: Optional[str] = None,
+    ) -> str:
+        if not kind:
+            kind = self._IDENTIFIER
+        values = {
+            "timestamp": str(self.timestamp),
+            "step": self.step,
+            kind: self.get_value(dump=True),
+        }
+
+        return json.dumps(values)
+
     def to_csv(self) -> str:
         values = [
             str(self.step) if self.step is not None else "",
@@ -417,8 +434,8 @@ def _read_jsonl(
             # Pyarrow automatically converts timestamp fields
             if "timestamp" in df.columns:
                 df["timestamp"] = df["timestamp"].astype(str)
-        if not hasattr(df, 'step'):
-            df['step'] = None
+        if not hasattr(df, "step"):
+            df["step"] = None
         return df
 
     @classmethod
@@ -515,7 +532,7 @@ def get_csv_events(self) -> str:
         return "".join(events)
 
     def get_jsonl_events(self) -> str:
-        events = ["\n{}".format(e.to_json()) for e in self.events]
+        events = ["\n{}".format(e.to_json(kind=self.kind)) for e in self.events]
         return "".join(events)
 
     def empty_events(self):

traceml/traceml/tracking/run.py

@@ -1225,9 +1225,7 @@ def log_html(
         logged_event = LoggedEventSpec(
             name=name,
             kind=V1ArtifactKind.HTML,
-            event=V1Event.make(
-                timestamp=timestamp, step=step, html=html.replace("\n", "")
-            ),
+            event=V1Event.make(timestamp=timestamp, step=step, html=html),
         )
         self._add_event(logged_event)