Has anyone ever used the File Channel Integrity Tool released as part of Flume 1.4.0? There is absolutely no documentation on it but an outstanding JIRA issue from last year to write some. 
I've been poking it with a stick as follows:
java -cp "/usr/lib/flume-ng/lib/*" org.apache.flume.tools.FlumeToolsMain FCINTEGRITYTOOL -l /path/to/.flume/file-channel/data/log-xxx
but it returns far too quickly with no output, and no apparent change in the data file.
I'm hoping it will help with a corrupt file channel error:
java.lang.IllegalStateException: Channel closed [channel=c_xxx]. Due to java.io.IOException: Unable to read next Transaction from log file /path/to/.flume/file-channel/data/log-xxx at offset 513457598
Caused by: com.google.protobuf.InvalidProtocolBufferException: While parsing a protocol message, the input ended unexpectedly in the middle of a field.  This could mean either than the input has been truncated or that an embedded message misreported its own length.