private List<Path> findFiles(Path workingDir, Predicate<Path> fileSelector) throws IOException {
    if (!workingDir.toFile().isDirectory()) {
      return Collections.emptyList();
    }
    try (Stream<Path> stream = Files.list(workingDir)) {
      return stream
          .filter(Files::isRegularFile)
          .filter(fileSelector)
          .filter(logFilter::acceptsFile)
          .collect(toList());
    }
  }
@return size of file in bytes
geode-gfsh/src/main/java/org/apache/geode/management/internal/cli/util/LogExporter.java