code: protected void doSend(Postcard postcard, SMailPostingMessage message) {
          logMailBefore(postcard, message);
          RuntimeException cause = null;
          try {
              retryableSend(postcard, message);
          } catch (RuntimeException e) {
              cause = e;
              if (postcard.isSuppressSendFailure()) {
                  logSuppressedCause(postcard, message, e);
              } else {
                  throw e;
              }
          } finally {
              logMailFinally(postcard, message, cause);
          }
      }
docs: ------------