How to dynamically select msmtp profile when sending a message?

[Adham Omran]

I am trying to set up Emacs to send from multiple accounts, but I am
facing two issues.

In my `/etc/msmtprc` configuration I have two accounts.

1. If one if the accounts is named `default` it always uses and never
automatically picks the correct account to send from based on my FROM
header.

2. If I rename `default` to anything else like `personal` Emacs just
fails to find anything to send from and throws

```
sendmail: account default not found in /etc/msmtprc
```

I want to be able to choose what account to send from, I fear this is
somehow hard coded or not under user choice.

Adham Omran