public ToStringBuilder appendToString(String toString) {
        if (toString != null) {
            style.appendToString(buffer, toString);
        }
        return this;
    }
<p>Append the <code>toString</code> from another object.</p>

<p>This method is useful where a class delegates most of the implementation of
its properties to another class. You can then call <code>toString()</code> on
the other class and pass the result into this method.</p>

<pre>
  private AnotherObject delegate;
  private String fieldInThisClass;

  public String toString() {
    return new ToStringBuilder(this).
      appendToString(delegate.toString()).
      append(fieldInThisClass).
      toString();
  }</pre>

<p>This method assumes that the other object uses the same <code>ToStringStyle</code>
as this one.</p>

<p>If the <code>toString</code> is <code>null</code>, no change is made.</p>

@param toString  the result of <code>toString()</code> on another object
@return this
@since 2.0
android/android_framework/base/src/main/java/lang3/builder/ToStringBuilder.java