### CONTEXT (Previous Events):
<system_output timestamp="3494.718432">I: Configuring tasksel-data...
</system_output>
<system_output timestamp="3494.75463">I: Configuring libc-bin...
</system_output>
<system_output timestamp="3494.854511">I: Base system installed successfully.
</system_output>
<system_output timestamp="3495.25808">Creating base.tar.xz
</system_output>
<system_output timestamp="3496.414229">Warning: no hostname for 172.16.0.17 found, not adding to /etc/hosts.
</system_output>
<system_output timestamp="3496.417628">... [TRUNCATED TO SAVE SPACE] ...</system_output>
<system_output timestamp="3496.423973">... [TRUNCATED TO SAVE SPACE] ...</system_output>
<system_output timestamp="3496.424988">... [TRUNCATED TO SAVE SPACE] ...</system_output>
<system_output timestamp="3496.664511">... [TRUNCATED TO SAVE SPACE] ...</system_output>
<system_output timestamp="3496.922919">Get:2 http://127.0.0.1:3142/ftp.de.debian.org/debian bookworm/main i386 Packages [8680 kB]
</system_output>
<system_output timestamp="3499.44153">Fetched 8831 kB in 3s (3102 kB/s)
Reading package lists...</system_output>
<system_output timestamp="3500.499277">
</system_output>
<system_output timestamp="3500.568295">Reading package lists...</system_output>
<system_output timestamp="3500.601554">
</system_output>

### TARGET LINE (Extract and Classify THIS Timestamp):
<system_output timestamp="3500.607508">Building dependency tree...</system_output>

Answer: 3500.607508, new event