@Nullable
    default String queryParam(String name) {
        return queryParams().get(name);
    }
Returns the value of a parameter with the specified {@code name}. If there are more than one value for
the specified {@code name}, the first value in insertion order is returned.

@param name the parameter name
@return the first parameter value if found, or {@code null} if there is no such parameter
core/src/main/java/com/linecorp/armeria/server/ServiceRequestContext.java