src/Structures/Buffer.php
public function offsetSet($index, $data)
    {
        $this->data = substr_replace($this->data, $data, $index, 1);
    }
public function offsetSet($index, $data)
    {
        $this->data = substr_replace($this->data, $data, $index, 1);
    }
Replaces the character in the buffer at the given position with the given string.

@param int $index
@param string $data