Three ways to clear StringBuilder and efficiency

It is known that frequent concatenation of strings is the use of StringBuilder. The Append method is much more efficient than using the string+= method, but sometimes you need to empty the StringBuilder without knowing how to empty it, because it does not have a clear or empty method. What's the way? Search the Internet for about three ways.

1. Remove

Cases:

New StringBuilder (); Val. Append (".... " ); Val. Remove (0, Val. Length); // Clear

2. Replace

New StringBuilder (); Val. Append (".... " ""); // Clear

3. Length

New StringBuilder (); Val. Append (".... "  0; // Clear

StringBuilder val = new StringBuilder ();
Val. Append ("....");
Val. Length = 0;//Empty

Three ways to clear StringBuilder and efficiency