Remove unnecessary byte[] allocation from CertificateRequest.CreateSelfSigned (#42776)

diff --git a/src/libraries/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/CertificateRequest.cs b/src/libraries/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/CertificateRequest.cs
index 9f4bf54..d1c6fc4 100644 (file)
--- a/src/libraries/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/CertificateRequest.cs
+++ b/src/libraries/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/CertificateRequest.cs
@@ -308,7 +308,7 @@ namespace System.Security.Cryptography.X509Certificates
 
             Debug.Assert(_generator != null);
 
-            byte[] serialNumber = new byte[8];
+            Span<byte> serialNumber = stackalloc byte[8];
             RandomNumberGenerator.Fill(serialNumber);
 
             using (X509Certificate2 certificate = Create(