code: private static NetFlowV5Header parseHeader(ByteBuf bb) {
          final int version = bb.readUnsignedShort();
          if (version != 5) {
              throw new InvalidFlowVersionException(version);
          }
  
          final int count = bb.readUnsignedShort();
          final long sysUptime = bb.readUnsignedInt();
          final long unixSecs = bb.readUnsignedInt();
          final long unixNsecs = bb.readUnsignedInt();
          final long flowSequence = bb.readUnsignedInt();
          final short engineType = bb.readUnsignedByte();
          final short engineId = bb.readUnsignedByte();
          final short sampling = bb.readShort();
          final int samplingMode = (sampling >> 14) & 3;
          final int samplingInterval = sampling & 0x3fff;
  
          return NetFlowV5Header.create(
                  version,
                  count,
                  sysUptime,
                  unixSecs,
                  unixNsecs,
                  flowSequence,
                  engineType,
                  engineId,
                  samplingMode,
                  samplingInterval);
      }
docs: <pre>
  | BYTES |     CONTENTS      |                                       DESCRIPTION                                        |
  |-------|-------------------|------------------------------------------------------------------------------------------|
  | 0-1   | version           | NetFlow export format version number                                                     |
  | 2-3   | count             | Number of flows exported in this packet (1-30)                                           |
  | 4-7   | sys_uptime        | Current time in milliseconds since the export device booted                              |
  | 8-11  | unix_secs         | Current count of seconds since 0000 UTC 1970                                             |
  | 12-15 | unix_nsecs        | Residual nanoseconds since 0000 UTC 1970                                                 |
  | 16-19 | flow_sequence     | Sequence counter of total flows seen                                                     |
  | 20    | engine_type       | Type of flow-switching engine                                                            |
  | 21    | engine_id         | Slot number of the flow-switching engine                                                 |
  | 22-23 | sampling_interval | First two bits hold the sampling mode; remaining 14 bits hold value of sampling interval |
  </pre>