code: public static void setCurrent(@Nullable String reason)
      {
          if (reason != null)
          {
              if (currentReason == null)
                  currentReason = new ThreadLocal<>();
              currentReason.set(reason);
          }
          else if (currentReason != null)
          {
              currentReason.remove();
          }
      }
docs: Sets the current reason that should be used for {@link net.dv8tion.jda.core.requests.restaction.AuditableRestAction AuditableRestAction}.
  
  @param reason
  The reason to use, or {@code null} to reset