docs: public Schema field(String fieldName, String fieldType) {
  		if (tableSchema.containsKey(fieldName)) {
  			throw new ValidationException("Duplicate field name $fieldName.");
  		}
  
  		LinkedHashMap<String, String> fieldProperties = new LinkedHashMap<>();
  		fieldProperties.put(SCHEMA_TYPE, fieldType);
  
  		tableSchema.put(fieldName, fieldProperties);
  
  		lastField = fieldName;
  		return this;
  	}