docs: @CheckForNull
      public String extractMemcachedId( @Nonnull final String sessionId ) {
          final int idxDash = sessionId.indexOf( '-' );
          if ( idxDash < 0 ) {
              return null;
          }
          final int idxDot = sessionId.indexOf( '.' );
          if ( idxDot < 0 ) {
              return sessionId.substring( idxDash + 1 );
          } else if ( idxDot < idxDash ) /* The dash was part of the jvmRoute */ {
              return null;
          } else {
              return sessionId.substring( idxDash + 1, idxDot );
          }
      }