Basic Infos

• This issue complies with the issue POLICY doc.
• I have read the documentation at readthedocs and the issue is not addressed there.
• I have tested that the issue is present in current master branch (aka latest git).
• I have searched the issue tracker for a similar issue.
• If there is a stack dump, I have decoded it.
• I have filled out all fields below.

Platform

• Hardware: all
• Core Version: latest git
• Development Env: all
• Operating System: all

Settings in IDE

• Module: all
• Flash Mode: all
• Flash Size: all
• lwip Variant: all
• Reset Method: all
• Flash Frequency: 40Mhz
• CPU Frequency: 80Mhz|160MHz
• Upload Using: SERIAL
• Upload Speed: 115200

Problem Description

This issue is meant to track pending changes to SPI::transferBytes, specifically a missing assert and some api optimizations.
Ref: #4925 #2677 .

edit 19/01/22 d-a-v: The API has to be clarified. transfer(buffer) and transferBytes(buffer) have the same signature, the first accepts unaligned buffer, not the second.