src/main/java/software/amazon/qldb/tutorial/model/streams/BlockSummaryRecord.java
src/main/java/software/amazon/qldb/tutorial/qldb/JournalBlock.java

src/main/java/software/amazon/qldb/tutorial/model/streams/Revision.java
src/main/java/software/amazon/qldb/tutorial/qldb/QldbRevision.java