SuperPowered TimeStretching - initial samples are not stretched

[petegoodliffe]

Superpowered version: 2.7.2

Describe the bug
Using Supwerpowered::TimeStretching, when pitch-shifted samples are played back, the first portion of the sample is played back at the original pitch rather than the new pitch.

Reproducibility
100%

Steps to Reproduce
Advanced Audio Player Repro:

• Launch demo at https://docs.superpowered.com/reference/latest/advanced-audio-player
• Apply a pitch shift (e.g. -12 Semitones)
• Select "Soaring quartet" (this is the easiest sample to hear it)
• Pause and Play the sample

Expected behavior
Sample plays at the selected pitch

Actual behavior
Initially the sample plays at its original pitch, before snapping to the correct new pitch. The timing of this likely varies, but it has been measured to be ~1900 samples long in our C++ application test case.

Device information
We see this on macOS, Windows, Linux, and your web demo test apps.

Log messages
Please share any log messages that may be relevant

Additional context
We can provide test audio files if required. (They are easy to generate)