AAudio
Android's low-latency C audio API, introduced in Android 8.0 as an attempt to make the phone usable as a musical instrument.
Android had a long-standing reputation among music developers: the same app that responded instantly on an iPhone lagged audibly on Android. The existing interface, OpenSL ES, was a general-purpose Khronos standard, clumsy to use, and audio went through several layers of buffering before it reached the hardware. AAudio shipped with Android 8.0 Oreo in 2017 with a narrower brief: open a stream, get a callback whenever the hardware wants more frames. From 8.1, streams in MMAP mode can write straight into the driver's buffer.
Since older phones lack AAudio, Google also released Oboe, a C++ library that picks AAudio where it exists and falls back to OpenSL ES otherwise. Actual round-trip latency still depends on the manufacturer's drivers – and phones differ there far more than any API can paper over.