Represents a string that supports efficient concatenation. This class is used instead of System.String when two strings are concatenated together using the addition operator (+) or the concat() function. Use of this class avoids the creation of useless intermediary strings and by doing so speeds up string concatenation dramatically (this change improved sunspider/string-validate-input.js by almost 20x).
 /// <summary>
 /// Appends the given string to the end of this object.
 /// </summary>
 /// <param name="str"> The string to append. </param>
 public void Append(ConcatenatedString str)
 {
     Append(str.ToString());
 }
 /// <summary>
 /// Appends the given string to the end of this object.
 /// </summary>
 /// <param name="str"> The string to append. </param>
 public void Append(ConcatenatedString str)
 {
     Append(str.ToString());
 }
 /// <summary>
 /// Returns a new ConcatenatedString instance containing the concatenation of this ConcatenatedString
 /// and the given string.
 /// </summary>
 /// <param name="str"> The string to append. </param>
 /// <returns> A new ConcatenatedString instance representing the concatenated string. </returns>
 public ConcatenatedString Concatenate(ConcatenatedString str)
 {
     return(Concatenate(str.ToString()));
 }
 /// <summary>
 /// Returns a new ConcatenatedString instance containing the concatenation of this ConcatenatedString
 /// and the given string.
 /// </summary>
 /// <param name="str"> The string to append. </param>
 /// <returns> A new ConcatenatedString instance representing the concatenated string. </returns>
 public ConcatenatedString Concatenate(ConcatenatedString str)
 {
     return Concatenate(str.ToString());
 }