code: public Field getField(String name) {
      if (fieldMap == null) {
        return null;
      }
      return fieldMap.get(name);
    }
docs: Returns the record {@link Field} of the given name.
  
  @param name Name of the field
  @return A {@link Field} or {@code null} if there is no such field in this record
  or this is not a {@link Type#RECORD RECORD} schema.