code: public static void serializeWriterDirPermissions(State state, int numBranches, int branchId,
        FsPermission fsPermissions) {
      serializeFsPermissions(state,
          ForkOperatorUtils.getPropertyNameForBranch(ConfigurationKeys.WRITER_DIR_PERMISSIONS, numBranches, branchId),
          fsPermissions);
    }
docs: Given a {@link FsPermission} objects, set a key, value pair in the given {@link State} for the writer to
  use when creating files. This method should be used in conjunction with {@link #deserializeWriterDirPermissions(State, int, int)}.