@NotNull public List<? extends XLineBreakpointVariant> computeVariants(@NotNull Project project,@NotNull XSourcePosition position){
  return Collections.emptyList();
}

@ NotNull public List < ? extends XLineBreakpointVariant > computeVariants ( @ NotNull Project project , @ NotNull XSourcePosition position ) { return Collections . emptyList ( ) ; }
return a list of variants if there can be more than one breakpoint on the line
