make constructor private

src/libraries/System.Net.Security/ref/System.Net.Security.cs

@@ -140,6 +140,7 @@ public static SslCertificateTrust CreateForX509Store(
         public static SslCertificateTrust CreateForX509Collection(
                                                 System.Security.Cryptography.X509Certificates.X509Certificate2Collection trustList,
                                                 bool sendTrustInHandshake = false) { throw null; }
+        private SslCertificateTrust() { throw null; }
    }
 
     public sealed partial class SslStreamCertificateContext

src/libraries/System.Net.Security/src/System/Net/Security/SslCertificateTrust.cs

@@ -58,5 +58,7 @@ public static SslCertificateTrust CreateForX509Collection(X509Certificate2Collec
             trust._sendTrustInHandshake = sendTrustInHandshake;
             return trust;
         }
+
+        private SslCertificateTrust() { }
     }
 }