The protobuf contrib provides a protocol buffer implementation and converter for the MATSim event infrastructure.
Add pb to the eventsFileFormat in your controller config.
<module name="controler">
<param name="outputDirectory" value="./output/example" />
<param name="firstIteration" value="0" />
<param name="lastIteration" value="1" />
<param name="eventsFileFormat" value="xml,pb"/>
</module>
The resulting files can be read with the MATSim python package and offer better performance than the xml variant.