v0.1.2

• Record while you play, on one I2S port. _audioif.rx_open() reads the RX
  half of the channel pair while audiobusio.I2SOut plays on the TX half, so a
  board whose speaker codec and microphone share a port (the ESP32-P4 boards)
  can do both at once. The output and the recorder each hold the channel and it
  closes when the last one lets go. I2SOut takes data_in= to open the pair,
  keeps the channel stereo while it can carry a recording, and refuses a sample
  at another rate while a recorder is open instead of retuning the bus under
  it. retarget() now also refuses a tail with another channel count, which
  used to play at twice or half speed.
  (#25)
• audiobusio.I2SOut.starved() reads 0 through a clean playback. It was
  the wire's position minus what the pump had fed, and that difference also
  carries how full the DMA ring is, so a clean playback on the ESP32-P4 read
  tens to thousands of bytes, a gc.collect() made it fall, and a real
  underrun read low by the ring's depth. It now counts two events in the DMA's
  interrupt: a descriptor started with nothing written into it (the ring ran
  dry), and a gap of more than two descriptor periods between finished
  descriptors (the DMA itself stood still, as a flash erase does on the
  ESP32-S3). Counting starts at the pump's first write after play() or
  resume(), stops at pause(), and only play() clears it, so the number
  never goes down and a pause is not counted.
  (#26)
• audiobusio.I2SOut(bit_clock, word_select, data) without port= opens. The
  default used to reach the driver as port -1 and fail with EIO; it now lets
  the driver choose the port, as on CircuitPython.
  (#27)