Stock callback usable as a git_cred_acquire_cb. This calls git_cred_userpass_plaintext_new unless the protocol has not specified GIT_CREDTYPE_USERPASS_PLAINTEXT as an allowed type.
The resource for which we are demanding a credential.
A bitmask stating which cred types are OK to return.
The payload provided when specifying this callback. (This is interpreted as a git_cred_userpass_payload*
.)