safe is not able to use a unix socket provided by a vault agent

[jouveits]

Vault agent (with auto-auth) can provide a local unix socket for other local clients to use (for instance vault cli).

Unfortunately, safe does not seem to be able to use it, unlike the vault cli:

# Poining the VAULT_ADDR to the socket provided by vault agent
$ export VAULT_ADDR=unix:///var/run/vault/agent.sock
# Local user can use it:
$ ls -l /var/run/vault/agent.sock
srwxrwx--- 1 vault vault 0 Jan 22 13:53 /var/run/vault/agent.sock
# Vault cli can use that socket, and use the authentication provided by vault agent:
$ vault kv list legacy/jouve-infradev
Keys
----
my-secrets/
# On the other end, safe is not able to use the socket:
$ $ safe version
safe v1.5.9
$ safe env
  VAULT_ADDR  unix:///var/run/vault/agent.sock
$ safe tree legacy
You are not authenticated to a Vault.
Try safe auth ldap
 or safe auth github
 or safe auth token
 or safe auth userpass
 or safe auth approle
$ safe auth status
Authenticating against  at unix:///var/run/vault/agent.sock
!! Transport Error: Get unix://:80//var/run/vault/agent.sock/v1/auth/token/lookup-self: unsupported protocol scheme "unix"

$ safe vault kv list legacy/jouve-infradev
Keys
----
my-secrets/