static void calcHdrVersion(int hdrSize) throws IOException {
    byte ver = (byte) (hdrSize >> 24);
    if (ver != HANDSHAKE_VERSION) {
      throw new IOException(
          format(
              "Detected wrong version of GemFire product during handshake. Expected %s but found %s",
              HANDSHAKE_VERSION, ver));
    }
  }
Returns true if an idle connection was detected.
geode-core/src/main/java/org/apache/geode/internal/tcp/Connection.java