title: Does google protocol buffers support size calculation before serialization?
body: <p>My (DSP) application produces data at a constant rate. The rate depends on the configuration that is selected by the user. I would like to know how many bytes are generated per second. The data structure contains a repeated (packed) floating point field. The length of the field is constant, but can be changed by the user.</p>
  
  <p>Is there a protocol buffers function that will calculate the message size before serialization?</p>