====================================
    Create a server plugin that can be used to retrieve a snapshot
    of the running system. Here we would support syntax to take a
    physical Snapshot of the database and store it in same
    machine/node where the database server is running.

    We should be able to start mysqld server on the cloned directory
    and access data. The clone operation should work with concurrent
    DMLs on the database.

    INSTALL PLUGIN clone SONAME 'mysql_clone.so';
    CLONE LOCAL DATA DIRECTORY [=] 'data_dir';
    UNINSTALL plugin clone;

    Review: rb#15068

    WL#9212: InnoDB: Monitor Clone status
    =====================================
    Support metadata view in performance schema to monitor progress
    of an ongoing clone operation. A clone operation might take time
    to clone the entire database. Administrator can view the current
    status and percentage of clone operation completed by querying
    this view in local and remote server.

    EVENT_NAME = "statement/sql/clone"
    EVENT_NAME = "stage/sql/clone (file copy)"
    EVENT_NAME = "stage/sql/clone (page copy)"
    EVENT_NAME = "stage/sql/clone (redo copy)"

    Review: rb#14160

    Merged from mysql-trunk-wl8953 [3db0acef]