Tested scenario 

Table a with a column the contains the number of the record, contains 1000 records. The connector starts and will snapshot these 1000 records. Then while streaming others 1000 records will be inserted on the same table, and at certain point a signal to execute blocking snapshot will be sent. The streaming stops at record with #1045. The blocking snapshot will snapshot again the table reading the first 1000 (same record from initial snapshot) and then about more ~45, (insert of records continues while snapshot from blocking snapshot request will effectively starts), let's say until record #1057. After the blocking snapshot finishes the streaming will resume from record #1046.