mapOrNull<TResult extends Object?>  method 
- @optionalTypeArgs
 
- TResult? repoRef(
- USubjectStatusViewSubjectRepoRef value
 
 - TResult? repoStrongRef(
- USubjectStatusViewSubjectRepoStrongRef value
 
 - TResult? messageRef(
- USubjectStatusViewSubjectMessageRef value
 
 - TResult? unknown(
- USubjectStatusViewSubjectUnknown value
 
 
A variant of map that fallback to returning null.
It is equivalent to doing:
switch (sealedClass) {
  case final Subclass value:
    return ...;
  case _:
    return null;
}
Implementation
@optionalTypeArgs TResult? mapOrNull<TResult extends Object?>({TResult? Function( USubjectStatusViewSubjectRepoRef value)?  repoRef,TResult? Function( USubjectStatusViewSubjectRepoStrongRef value)?  repoStrongRef,TResult? Function( USubjectStatusViewSubjectMessageRef value)?  messageRef,TResult? Function( USubjectStatusViewSubjectUnknown value)?  unknown,}){
final _that = this;
switch (_that) {
case USubjectStatusViewSubjectRepoRef() when repoRef != null:
return repoRef(_that);case USubjectStatusViewSubjectRepoStrongRef() when repoStrongRef != null:
return repoStrongRef(_that);case USubjectStatusViewSubjectMessageRef() when messageRef != null:
return messageRef(_that);case USubjectStatusViewSubjectUnknown() when unknown != null:
return unknown(_that);case _:
  return null;
}
}