void (final int bytesWritten, final long writeStartedAtNs) { assert bytesWritten >= 0 : "bytesWritten must be >=0, " + bytesWritten; totalPagesWritten.incrementAndGet(); totalBytesWritten.addAndGet(bytesWritten); if (MEASURE_TIMESTAMPS) { totalPagesWriteNs.addAndGet(System.nanoTime() - writeStartedAtNs); } }