private static OutputStream maybeWrapStatsOutputStream( OutputStream outputStream, CompressingFilterContext context, CompressingFilterStats.StatsField field) { assert outputStream != null; OutputStream result; if (context.isStatsEnabled()) { CompressingFilterStats stats = context.getStats(); CompressingFilterStats.OutputStatsCallback callbackOutput = stats.getOutputStatsCallback(field); result = new StatsOutputStream(outputStream, callbackOutput); } else { result = outputStream; } return result; }