The Bus: set_buffers() hit assert during async xfer handling afer unlock()

[forGGe]

Following call order leads to assertion hit:

• lock() - bus is locked
• xfer(callback) - async xfer scheduled
• unlock() - schedule unlocking
• Interrupt occur, callback is called
• New buffers tried to be set with set_buffers() call
• assert hits in ecl_assert(m_state & bus_locked);

See: https://github.com/forGGe/theCore/blob/master/dev/bus/export/dev/bus.hpp#L321

One of possible solution is to reject is as expected, since unlocked bus must support very limited functionality, e.g. setting buffers shouldn't be allowed outsize of interrupt.

[forGGe]

Not enough cases to analyze. Postponed.