nvm: big sur + zsh: `nvm_supports_source_options` is very slow

Operating system and version:

MacOS Big Sur version 11.0.1 (20B29)

nvm debug output:

nvm --version: v0.37.2
$TERM_PROGRAM: iTerm.app
$SHELL: /bin/zsh
$SHLVL: 1
$PREFIX: ''
${NPM_CONFIG_PREFIX}: ''
$NVM_NODEJS_ORG_MIRROR: ''
$NVM_IOJS_ORG_MIRROR: ''
shell version: 'zsh 5.8 (x86_64-apple-darwin20.0)'
uname -a: 'Darwin 20.1.0 Darwin Kernel Version 20.1.0: Sat Oct 31 00:07:11 PDT 2020; root:xnu-7195.50.7~2/RELEASE_X86_64 x86_64'
checksum binary: 'shasum'
OS version: macOS 11.0.1 20B29
curl: /usr/bin/curl, curl 7.64.1 (x86_64-apple-darwin20.0) libcurl/7.64.1 (SecureTransport) LibreSSL/2.8.3 zlib/1.2.11 nghttp2/1.41.0
Warning: Failed to set locale category LC_NUMERIC to en_IN.
Warning: Failed to set locale category LC_TIME to en_IN.
Warning: Failed to set locale category LC_COLLATE to en_IN.
Warning: Failed to set locale category LC_MONETARY to en_IN.
Warning: Failed to set locale category LC_MESSAGES to en_IN.
wget: /usr/local/bin/wget, GNU Wget 1.20.3 built on darwin19.0.0.
sed: /usr/bin/sed
cut: /usr/bin/cut
basename: /usr/bin/basename
rm: /bin/rm
mkdir: /bin/mkdir
xargs: /usr/bin/xargs
git: /usr/local/bin/git, git version 2.15.1
ls: grep:: No such file or directory
grep: grep: aliased to grep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox} (grep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox}), grep (BSD grep) 2.5.1-FreeBSD
awk: /usr/bin/awk, awk version 20200816
nvm current: none
which node: node not found
which iojs: iojs not found
which npm: npm not found
npm config get prefix: nvm:279: command not found: npm
npm root -g: nvm:279: command not found: npm

nvm ls output:

        v8.15.1
       v10.16.0
       v10.18.0
       v10.21.0
default -> 10.21.0 (-> v10.21.0)
iojs -> N/A (default)
unstable -> N/A (default)
node -> stable (-> v10.21.0) (default)
stable -> 10.21 (-> v10.21.0) (default)
lts/* -> lts/erbium (-> N/A)
lts/argon -> v4.9.1 (-> N/A)
lts/boron -> v6.17.1 (-> N/A)
lts/carbon -> v8.17.0 (-> N/A)
lts/dubnium -> v10.22.1 (-> N/A)
lts/erbium -> v12.19.0 (-> N/A)

How did you install nvm?

Used to have nvm via brew. But removed it and used the install script after git clone

What steps did you perform?

1. Opening a new ITerm2 window
2. Opening a new ITerm2 tab

What happened?

Window/each tab opens very slow

What did you expect to happen?

Window/Tab opens faster (much faster)

Is there anything in any of your profile files that modifies the PATH?

I use .zshrc. It just loads .oh-my-zsh In my bash_profile.zsh in .oh-my-zsh, below is one change to PATH PATH="/usr/local/sbin:$PATH"

Below is out of profiling using zprof

Without --no-use while loading nvm

New iTerm2 window

num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)    1        5097.89  5097.89   82.35%   5097.89  5097.89   82.35%  nvm_supports_source_options
 2)    1         858.57   858.57   13.87%    298.37   298.37    4.82%  nvm_auto
 3)    2         560.20   280.10    9.05%    285.03   142.52    4.60%  nvm
 4)    1         186.51   186.51    3.01%    171.74   171.74    2.77%  nvm_ensure_version_installed
 5)    1          82.37    82.37    1.33%     82.37    82.37    1.33%  handle_completion_insecurities
 6)    4          61.38    15.35    0.99%     54.81    13.70    0.89%  nvm_npmrc_bad_news_bears
 7)    2          75.70    37.85    1.22%     54.69    27.35    0.88%  compinit

New tab

num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)    1        5090.09  5090.09   84.73%   5090.09  5090.09   84.73%  nvm_supports_source_options
 2)    2         493.81   246.90    8.22%    277.37   138.68    4.62%  nvm
 3)    1         763.55   763.55   12.71%    269.75   269.75    4.49%  nvm_auto
 4)    1         191.82   191.82    3.19%    176.35   176.35    2.94%  nvm_ensure_version_installed
 5)    2          71.90    35.95    1.20%     49.42    24.71    0.82%  compinit
 6)    1          27.22    27.22    0.45%     27.22    27.22    0.45%  handle_completion_insecurities
 7)    2          22.47    11.24    0.37%     22.47    11.24    0.37%  compaudit

With --no-use

New Window

num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)    1        5092.37  5092.37   96.67%   5092.37  5092.37   96.67%  nvm_supports_source_options
 2)    2          84.06    42.03    1.60%     51.88    25.94    0.98%  compinit
 3)    2          32.19    16.09    0.61%     32.19    16.09    0.61%  compaudit

New Tab

num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)    1        5090.18  5090.18   96.92%   5090.18  5090.18   96.92%  nvm_supports_source_options
 2)    2          75.79    37.90    1.44%     51.48    25.74    0.98%  compinit
 3)    1          26.25    26.25    0.50%     26.25    26.25    0.50%  handle_completion_insecurities

Please let me know if you need any further details. This slowness was conspicuous after Big Sur update. My doubt is same as this comment https://github.com/nvm-sh/nvm/issues/1978#issuecomment-452954807 about source not working fine