Using the TFS ExtendedClient Nuget package, we can extract identities using these actions:
TeamFoundationIdentity tfi = ims.ReadIdentity(IdentitySearchFactor.AccountName, "[DefaultCollection]\\Project Collection Valid Users", MembershipQuery.Expanded, ReadIdentityOptions.None);
TeamFoundationIdentity[] ids = ims.ReadIdentities(tfi.Members, MembershipQuery.None, ReadIdentityOptions.None);
This is the equivalent of sending this API call with different query params: http://TFS/COLLECTION/_apis/identities?queryMembership=None
I'm trying to find the exact API calls with query params to achieve the same actions as in the Nuget package actions example.