Pass state in to_html (#726)

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lonboard/_map.py

@@ -545,6 +545,9 @@ def inner(fp):
                 title=title or "Lonboard export",
                 template=_HTML_TEMPLATE,
                 drop_defaults=False,
+                # Necessary to pass the state of _this_ specific map. Otherwise, the
+                # state of all known widgets will be included, ballooning the file size.
+                state=self.get_state(),
             )
 
         if filename is None: