code: public static FreeContext mergeFrom(FreePOptions.Builder optionsBuilder) {
      FreePOptions masterOptions = FileSystemOptions.freeDefaults(ServerConfiguration.global());
      FreePOptions.Builder mergedOptionsBuilder =
          masterOptions.toBuilder().mergeFrom(optionsBuilder.build());
      return create(mergedOptionsBuilder);
    }
docs: Merges and embeds the given {@link FreePOptions} with the corresponding master options.
  
  @param optionsBuilder Builder for proto {@link FreePOptions} to merge with defaults
  @return the instance of {@link FreeContext} with default values for master