Unable to update resource pack while on server

When a joined server uses a custom resource pack and provides a hash for <URL>, there is no possibility to update the enabled pack (same url, new hash) while the player is online. Instead, the Minecraft client notices the mismatch between existing and provided hash, resulting in an attempt to delete the file. Here is the problem: It seems that Minecraft does not unload already applied server resource pack files (without disconnecting) before trying to delete them. This results in a SHARING VIOLATION on the client's file system and Minecraft ignoring the custom pack. This state can only be fixed by restarting the client.

Although there is no possibility to re-send the Packet 0x39 with vanilla servers, IMHO the packet's usage implies that this should be possible.

Snippet from log with old hash being 6218288 and new (sent) hash a4947c2:

[22:16:57] [Netty Client IO #5/WARN]: File C:\Users\USER\AppData\Roaming\.minecraft\server-resource-packs\3c382705db44fa7a15e9c07554d828a02e717b5f had wrong hash (expected a4947c24055c940f25fcd9603c4f28249512a0f2, found 62182881976c9edb1d2dd7bd48ffe1aba342d509).
[22:16:57] [Netty Client IO #5/WARN]: Pack application failed: Hash check failure for file C:\Users\USER\AppData\Roaming\.minecraft\server-resource-packs\3c382705db44fa7a15e9c07554d828a02e717b5f, see log, deleting file C:\Users\noahg\AppData\Roaming\.minecraft\server-resource-packs\3c382705db44fa7a15e9c07554d828a02e717b5f
[22:16:57] [Netty Client IO #5/WARN]: Failed to delete file C:\Users\USER\AppData\Roaming\.minecraft\server-resource-packs\3c382705db44fa7a15e9c07554d828a02e717b5f: C:\Users\noahg\AppData\Roaming\.minecraft\server-resource-packs\3c382705db44fa7a15e9c07554d828a02e717b5f: Der Prozess kann nicht auf die Datei zugreifen, da sie von einem anderen Prozess verwendet wird.*

*"the process cannot access the file because it is being used by another process"