AL_SAMPLE_OFFSET Problem

I did some further investigating and found that:

1. Setting AL_SAMPLE_OFFSET (or AL_BYTE_OFFSET or AL_SEC_OFFSET) with alSourcei does, in fact, change the offset value if the source is stopped.
2. Calling alSourcePlay on the source resets the AL_SAMPLE_OFFSET to 0.
3. Calling alSourcei with AL_SAMPLE_OFFSET while the sound is playing has no effect at all.

The latter two points are in direct conflict with OpenAL specifications, which state that:

> When setting AL_SAMPLE_OFFSET on a source which is already playing, the playback
> will jump to the new offset unless the new offset is out of range, in which case an
> AL_INVALID_VALUE error is set. If the source is not playing, then the offset will be
> applied on the next alSourcePlay call. An alSourceStop, alSourceRewind, or a second
> alSourcePlay call will reset the offset to the beginning of the buffer

_Originally posted by @JacksonAllan in https://github.com/emscripten-core/emscripten/issues/3271#issuecomment-459155176_

I have the same issue as JacksonAllan. When i pause and replay a source, the offset is reset to 0. Is it a bug for AL_SAMPLE_OFFSET implementation or something special should be done to fix this problem?