@Override
    public String apply(T object) {
        final StringJoiner joiner = new StringJoiner(separator, prefix, suffix);
        joiner.add(first.apply(object));
        joiner.add(second.apply(object));
        return joiner.toString();
    }
The default implementation of {@link JoiningExpression}.

@author Emil Forslund
@since  3.1.0
runtime-parent/runtime-compute/src/main/java/com/speedment/runtime/compute/internal/BinaryJoiningExpressionImpl.java