src/V2/Schema/SchemaHandler.php
public function onRequest( RequestInterface $request ) {
        $schema = $this->getEndpoint()->getSchema();

        return $request->withHeader( 'X-Schema-Version', $schema );
    }
public function onRequest( RequestInterface $request ) {
        $schema = $this->getEndpoint()->getSchema();

        return $request->withHeader( 'X-Schema-Version', $schema );
    }
public function onRequest ( RequestInterface $ request ) { $ schema = $ this -> getEndpoint ( ) -> getSchema ( ) ; return $ request -> withHeader ( 'X-Schema-Version' , $ schema ) ; }
Add the schema version header.

@param RequestInterface $request

@return MessageInterface|RequestInterface
Add the schema version header .