@Override
    public Builder toBuilder() {
        return builder()
                .type(type)
                .name(name)
                .builtIn(builtIn)
                .value(value)
                .required(required)
                .sourceLocation(sourceLocation)
                .deprecated(deprecated)
                .documentation(documentation)
                .defaultValue(defaultValue);
    }
Gets the parameter's default value.

@return returns the optional default value.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/syntax/parameters/Parameter.java