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writeln method
- [Object? obj = ""]
    override
   
  Writes object followed by a newline, "\n".
Calling writeln(null) will write the "null" string before the newline.
Implementation
external void writeln([Object? obj = ""]);© 2012 the Dart project authors
Licensed under the BSD 3-Clause "New" or "Revised" License.
 https://api.dart.dev/stable/2.18.5/dart-core/StringBuffer/writeln.html