i2c peripheral is not using a repeated start condition for write_read()

[liebman]

A logic analyser shows that a stop condition followed by start condition is currently being issued instead of the repeated start.

Both embedded-hal and embedded-hal-async specify that write_read() uses a repeated start condition.

Some devices like the veml7700 require a repeated start. See Fig. 4 - I2C Bus Timing for Receive Word Command Format on page 4.

[bjoernQ]

Probably the best thing to do would be to support https://docs.rs/embedded-hal/latest/embedded_hal/i2c/trait.I2c.html#tymethod.transaction - for the embedded-hal trait the provided methods will use it and things should be fine