@Override
    public String toString() {
        return value;
    }
Gets the optional structured syntax suffix.

<p>For example given, "application/foo+json", this method returns
"json". Given "application/foo+baz+json", this method returns
"json". Given "application/json", this method returns an empty
{@code Optional}.

@return Returns the optional structured syntax suffix value with no "+".
smithy-utils/src/main/java/software/amazon/smithy/utils/MediaType.java