message: burst buffer: update doc
diff: @@ -68,11 +68,11 @@ This engine allows the user to fine tune the buffering operations through the fo
  12. **StatsBlockSize**: Calculate Min/Max for a given size of each process output. Default is one Min/Max per writer. More fine-grained min/max can be useful for querying the data.
  -13. **NodeLocal** or **Node-Local**: For distributed file system. Every writer process must make sure the .bp/ directory is created on the local file system. Required for using local disk/SSD/NVMe in a cluster.
  +13. **NodeLocal** or **Node-Local**: For distributed file system. Every writer process must make sure the .bp/ directory is created on the local file system. Required when writing to local disk/SSD/NVMe in a cluster. Note: the BurstBuffer* parameters are newer and should be used for using the local storage as temporary instead of this parameter.
  -14. **BurstBufferPath**: Redirect output file to another location and drain it to the original target location in an asynchronous thread. It requires to be able to launch one thread per aggregator (see SubStreams) on the system. This feature can be used on machines that have local NVMe/SSDs on each node to accelerate the output writing speed. On Summit at OLCF, use "/mnt/bb/<username>" for the path where <username> is your user account name. Note: ADIOS does not remove the data on the accelerated storage after draining to the file system.
  +14. **BurstBufferPath**: Redirect output file to another location and drain it to the original target location in an asynchronous thread. It requires to be able to launch one thread per aggregator (see SubStreams) on the system. This feature can be used on machines that have local NVMe/SSDs on each node to accelerate the output writing speed. On Summit at OLCF, use "/mnt/bb/<username>" for the path where <username> is your user account name. Temporary files on the accelerated storage will be automatically deleted after the application closes the output and ADIOS drains all data to the file system, unless draining is turned off (see the next parameter). Note: at this time, this feature cannot be used to append data to an existing dataset on the target system.
  -15. **BurstBufferDrain**: To write only to the accelerated storage but do not drain it to the target file system, set this flag to false. By default, setting the BurstBufferPath will turn on draining.
  +15. **BurstBufferDrain**: To write only to the accelerated storage but to not drain it to the target file system, set this flag to false. Data will NOT be deleted from the accelerated storage on close. By default, setting the BurstBufferPath will turn on draining.
  16. **BurstBufferVerbose**: Verbose level 1 will cause each draining thread to print a one line report at the end (to standard output) about where it has spent its time and the number of bytes moved. Verbose level 2 will cause each thread to print a line for each draining operation (file creation, copy block, write block from memory, etc).
  