Reader should name fields only with their field name
The Legacy VTK file reader was augmenting all the field names with the type of field. For example, if you had a point scalar field named "elevation", it would be loaded as "SCALARS:elevation".
This is bad for two reasons. First, it is downright confusing. A tool like ParaView or VisIt will tell me the field is named "elevation", but VTK-m will report that field does not exist. Second, the writer does not follow the same convention. Thus, if you have a loop of read file, modify, write file, you could end up with fields named "SCALARS:SCALARS:SCALARS:...".