Clarified in Javadoc that $snapshot only prevents duplicates.
Clarified in Javadoc that $snapshot only prevents duplicates.

JAVA-1408

jsonking/mongo-java-driver,rozza/mongo-java-driver,gianpaj/mongo-java-driver,jyemin/mongo-java-driver,jyemin/mongo-java-driver,rozza/mongo-java-driver,kay-kim/mongo-java-driver,jsonking/mongo-java-driver,PSCGroup/mongo-java-driver