@CanIgnoreReturnValue
    public Builder setWorkingDirectory(String workingDirectory) {
      PathType.ParseResult parseResult = pathType.parsePath(workingDirectory);
      checkArgument(
          parseResult.isAbsolute(),
          "working directory must be an absolute path: %s",
          workingDirectory);
      this.workingDirectory = checkNotNull(workingDirectory);
      return this;
    }
Sets the path to the working directory for the file system. The working directory must be an
absolute path starting with one of the configured roots.

@throws InvalidPathException if the given path is not valid for this builder's path type
@throws IllegalArgumentException if the given path is valid for this builder's path type but
    is not an absolute path
jimfs/src/main/java/com/google/common/jimfs/Configuration.java