public record FhirPatientUpsertRequest(
    string IdentifierSystem,
    string IdentifierValue,
    string FirstName,
    string LastName,
    DateOnly DateOfBirth,
    string Gender,
    BloodType? BloodType = null,
    string? Allergies = null,
    string? EmergencyContactName = null,
    string? EmergencyContactPhone = null);