Missing mutex synchronization in AudioBuffer::freeSpace() in schreibfaul1 ESP32-audioI2S 3.4.5...

Missing mutex synchronization in AudioBuffer::freeSpace() in schreibfaul1 ESP32-audioI2S 3.4.5 creates a race condition between concurrent tasks. The function calculates available buffer space without protecting shared read/write pointers, returning an incorrectly large value. Trusting this value leads to heap out-of-bounds write, memory corruption, device crash, and arbitrary code execution.