DESCRIPTION
Emacs 27.1 has a bug related to HTTP(S) downloads and/or package compilation
that causes downloads and compilation of ELPA packages using Quelpa
(https://github.com/quelpa/quelpa) to fail. Compilation of downloaded files
gives an error: "error in process sentinel: End of file during parsing". 

Being a bit of a novice, it is hard for me to pinpoint the error, but it's
reproducible when installing the Spacemacs Emacs distribution
(https://github.com/syl20bnr/spacemacs/). This is because Spacemacs, upon
installation, downloads and installs lots of packages. This will yield dozens
of "end of file during parsing" messages.

This error is usually indicative of missed parentheses, but it seems to be
related to the download operation, because (a) it is not reproducible (it
concerns different files every time), and (b) the files in question are
downloaded from their master repositories and are unlikely to contain missing
parentheses.

HOW TO REPRODUCE

Installation of Spacemacs according to the recommended procedure:
- Delete ./emacs.d
- Delete .spacemacs
- Download spacemacs using `git clone --branch develop
https://github.com/syl20bnr/spacemacs ~/.emacs.d` 
- Start Emacs 27.1.

EXPECTED BEHAVIOUR

Clean installation of Spacemacs.

OBSERVED BEHAVIOUR

Spacemacs begins downloading and compiling packages from ELPA. A significant,
but not reproducible number of these fail to compile and give the following
error message:

error in process sentinel: async-handle-result: End of file during parsing
error in process sentinel: End of file during parsing

This happens regardless of whether I use the "develop" (0.300) or the stable
"master" (0.200) branch of Spacemacs, and regardless of whether I use HTTPS or
HTTP (with `emacs --insecure`).

Different packages are concerned every time.

Two examples of messages from this installation are here: 
https://pastebin.com/AzPJ0FZr and https://pastebin.com/VQzD6zgY