driver-legacy/src/main/com/mongodb/Mongo.java
@Deprecated
    public DBObject unlock() {
        return DBObjects.toDBObject(createOperationExecutor().execute(new FsyncUnlockOperation(), readPreference, readConcern));
    }
@Deprecated
    public DBObject unlock() {
        return DBObjects.toDBObject(createOperationExecutor().execute(new FsyncUnlockOperation(), readPreference, readConcern));
    }
Unlocks the database, allowing the write operations to go through. This command may be asynchronous on the server, which means there
may be a small delay before the database becomes writable.

@return {@code DBObject} in the following form {@code {"ok": 1,"info": "unlock completed"}}
@throws MongoException if there's a failure
@mongodb.driver.manual reference/command/fsync/ fsync command