src/Utils/MixedStore.php
public function offsetUnset($offset)
    {
        if ($offset === true) {
            $this->trueValue      = null;
            $this->trueValueIsSet = false;
        } elseif ($offset === false) {
            $this->falseValue      = null;
            $this->falseValueIsSet = false;
        } elseif (is_int($offset) || is_string($offset)) {
            unset($this->standardStore[$offset]);
        } elseif (is_float($offset)) {
            unset($this->floatStore[(string) $offset]);
        } elseif (is_object($offset)) {
            $this->objectStore->offsetUnset($offset);
        } elseif (is_array($offset)) {
            $index = array_search($offset, $this->arrayKeys, true);

            if ($index !== false) {
                array_splice($this->arrayKeys, $index, 1);
                array_splice($this->arrayValues, $index, 1);
            }
        } elseif ($offset === null) {
            $this->nullValue      = null;
            $this->nullValueIsSet = false;
        }
    }
public function offsetUnset($offset)
    {
        if ($offset === true) {
            $this->trueValue      = null;
            $this->trueValueIsSet = false;
        } elseif ($offset === false) {
            $this->falseValue      = null;
            $this->falseValueIsSet = false;
        } elseif (is_int($offset) || is_string($offset)) {
            unset($this->standardStore[$offset]);
        } elseif (is_float($offset)) {
            unset($this->floatStore[(string) $offset]);
        } elseif (is_object($offset)) {
            $this->objectStore->offsetUnset($offset);
        } elseif (is_array($offset)) {
            $index = array_search($offset, $this->arrayKeys, true);

            if ($index !== false) {
                array_splice($this->arrayKeys, $index, 1);
                array_splice($this->arrayValues, $index, 1);
            }
        } elseif ($offset === null) {
            $this->nullValue      = null;
            $this->nullValueIsSet = false;
        }
    }
Offset to unset

@link http://php.net/manual/en/arrayaccess.offsetunset.php

@param mixed $offset <p>
The offset to unset.
</p>

@return void