public void addStartBytecodeMapping(int bytecodeOffset) {
    if (myDebugTrace != null) {
      myDebugTrace.myPreventDeletion = true;
    }
    myBytecodeOffsetMapping.putIfAbsent(new BytecodeMappingKey(bytecodeOffset, null, null), 0);
  }
If the current group is applied, add a newline here. Otherwise, add the argument.
If {@code dedent} is true, the extra indent from this group is unapplied from this point on.
src/org/jetbrains/java/decompiler/util/TextBuffer.java