public Class<?> getResultType() {
        return resultType;
    }
Extracts information from Ribbon annotated method, to automatically populate the Ribbon request template.
A few validations are performed as well:
- a return type must be {@link com.netflix.ribbon.RibbonRequest}
- HTTP method must be always specified explicitly (there are no defaults)
- only one parameter with {@link com.netflix.ribbon.proxy.annotation.Content} annotation is allowed

@author Tomasz Bak
ribbon/src/main/java/com/netflix/ribbon/proxy/MethodTemplate.java