effectiveUnderlying property
The underlying SymbolInfo. Falls back to parseSymInfo when
underlyingSymbolInfo is null (i.e. the charted symbol is itself
the underlying).
Implementation
SymbolInfo get effectiveUnderlying =>
underlyingSymbolInfo != null && underlyingSymbolInfo!.isNotEmpty
? SymbolInfo.fromJson(jsonDecode(underlyingSymbolInfo!))
: parseSymInfo;