How does the author use foreshadowing in Sharpe's Trafalgar: Richard Sharpe and the Battle of Trafalgar, October 21, 1805?

In Chapter Three, the conversation between Sharpe and Pohlmann regarding the hostilities between the French and English is important because it foreshadows events to come. The foreshadowing in this case is not overly obvious, but what eventually occurs indicates Pohlmann's reason for being on the ship. It will eventually be revealed that Pohlmann, Cromwell and another man have joined forces to hand the Calliope over to the French.