code: public static String newLoggerName(@Nullable String pathish) {
          if (pathish == null) {
              return UNKNOWN_LOGGER_NAME;
          }
  
          String normalized = pathish;
          if ("/".equals(normalized)) {
              return ROOT_LOGGER_NAME;
          }
  
          if (normalized.startsWith("/")) {
              normalized = normalized.substring(1); // Strip the first slash.
          }
  
          final int end;
          if (normalized.endsWith("/")) {
              end = normalized.length() - 1;
          } else {
              end = normalized.length();
          }
  
          final StringBuilder buf = new StringBuilder(end);
          boolean start = true;
          for (int i = 0; i < end; i++) {
              final char ch = normalized.charAt(i);
              if (ch != '/') {
                  if (start) {
                      start = false;
                      if (Character.isJavaIdentifierStart(ch)) {
                          buf.append(ch);
                      } else {
                          buf.append('_');
                          if (Character.isJavaIdentifierPart(ch)) {
                              buf.append(ch);
                          }
                      }
                  } else {
                      if (Character.isJavaIdentifierPart(ch)) {
                          buf.append(ch);
                      } else {
                          buf.append('_');
                      }
                  }
              } else {
                  start = true;
                  buf.append('.');
              }
          }
  
          return buf.toString();
      }
docs: Returns the logger name from the specified {@code pathish}.