@Deprecated
  public BufferedMutatorParams implementationClassName(String implementationClassName) {
    this.implementationClassName = implementationClassName;
    return this;
  }
Specify a BufferedMutator implementation other than the default.
@param implementationClassName Name of the BufferedMutator implementation class
@deprecated Since 3.0.0, will be removed in 4.0.0. You can not set it any more as the
            implementation has to use too many internal stuffs in HBase.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/BufferedMutatorParams.java