Pending livestream thumbnail key after presign (before complete). Use bucket lifecycle rules on
temp/livestreams/thumbnail-pending/ to prune abandoned uploads.
Parameters
userId: string
Owner user id.
livestreamId: string
Livestream row id.
uniqueId: string
Unique filename segment (e.g. UUID).
extension: string
File extension with or without a leading dot (e.g. jpg, .png).
Pending livestream thumbnail key after presign (before complete). Use bucket lifecycle rules on
temp/livestreams/thumbnail-pending/to prune abandoned uploads.