code: public function isCompatibleForMerge(Field $other)
      {
          if ($this->name !== $other->name) {
              return false;
          }
  
          if ($this->type !== $other->type) {
              return false;
          }
  
          if ($this->rule !== $other->rule) {
              return false;
          }
  
          if ($this->className !== $other->className) {
              return false;
          }
  
          if (!array_intersect($this->anyOfClassNames, $other->anyOfClassNames)) {
              return false;
          }
  
          return true;
      }
docs: Returns true if this field is likely compatible with the
  provided field during a mergeFrom operation.
  
  todo: implement/test isCompatibleForMerge
  
  @param Field $other
  
  @return bool