try {
segnOutput = new ChecksumIndexOutput(directory.createOutput(segmentsFileName, IOContext.DEFAULT));
CodecUtil.writeHeader(segnOutput, "segments", VERSION_46);
segnOutput.writeLong(version);
segnOutput.writeInt(counter); // write counter
segnOutput.writeInt(size()); // write infos
for (SegmentCommitInfo siPerCommit : this) {
SegmentInfo si = siPerCommit.info;
segnOutput.writeString(si.name);
segnOutput.writeString(si.getCodec().getName());