src/Message/Server/Request.php
public function withAttribute($name, $value)
    {
        $request = clone $this;
        $request->attributes[$name] = $value;
        return $request;
    }
public function withAttribute($name, $value)
    {
        $request = clone $this;
        $request->attributes[$name] = $value;
        return $request;
    }
Return an instance with the specified derived request attribute.

This method allows setting a single derived request attribute as
described in getAttributes().

@see getAttributes()
@param string $name The attribute name.
@param mixed $value The value of the attribute.

@return Request