code: public Csv schema(TypeInformation<Row> schemaType) {
  		Preconditions.checkNotNull(schemaType);
  		internalProperties.putString(FORMAT_SCHEMA, TypeStringUtils.writeTypeInfo(schemaType));
  		return this;
  	}
docs: Sets the format schema with field names and the types. Required if schema is not derived.
  
  @param schemaType type information that describes the schema