code: func NewFieldFromReader(name string, reader io.RuneReader, ft *FieldType) *Field {
  	assert2(name != "", "name cannot be empty")
  	assert2(ft != nil, "type can not be nil")
  	assert2(reader != nil, "reader cannot be nil")
  	assert2(!ft.Stored(), "fields with a Reader value cannot be stored")
  	assert2(!ft.Indexed() || ft.Tokenized(), "non-tokenized fields must use String values")
  	return &Field{ft, name, reader, 1.0, nil}
  }
docs: /* Create field with Reader value. */