code: @Override
    public Double incrByFloat(final byte[] key, final double increment) {
      checkIsInMultiOrPipeline();
      client.incrByFloat(key, increment);
      String dval = client.getBulkReply();
      return (dval != null ? new Double(dval) : null);
    }
docs: INCRBYFLOAT work just like {@link #incrBy(byte[], long)} INCRBY} but increments by floats
  instead of integers.
  <p>
  INCRBYFLOAT commands are limited to double precision floating point values.
  <p>
  Note: this is actually a string operation, that is, in Redis there are not "double" types.
  Simply the string stored at the key is parsed as a base double precision floating point value,
  incremented, and then converted back as a string. There is no DECRYBYFLOAT but providing a
  negative value will work as expected.
  <p>
  Time complexity: O(1)
  @see #incr(byte[])
  @see #decr(byte[])
  @see #decrBy(byte[], long)
  @param key the key to increment
  @param increment the value to increment by
  @return Integer reply, this commands will reply with the new value of key after the increment.