Allow Bcc in header (#81)

Fix #38

README.md

@@ -82,7 +82,9 @@ Go Simple Mail supports:
 
 https://pkg.go.dev/github.com/xhit/go-simple-mail/v2?tab=doc
 
-Note: by default duplicated recipients throws an error, from `v2.13.0` you can use `email.AllowDuplicateAddress = true` to avoid the check.
+Note 1: by default duplicated recipients throws an error, from `v2.13.0` you can use `email.AllowDuplicateAddress = true` to avoid the check.
+
+Note 2: by default Bcc header is not set in email. From `v2.14.0` you can use `email.AddBccToHeader = true` to add this.
 
 ## Download
 

email.go

@@ -32,6 +32,7 @@ type Email struct {
 	SMTPServer            *smtpClient
 	DkimMsg               string
 	AllowDuplicateAddress bool
+	AddBccToHeader        bool
 }
 
 /*
@@ -349,6 +350,11 @@ func (email *Email) AddAddresses(header string, addresses ...string) *Email {
 			return email
 		}
 
+		// add Bcc only if AddBccToHeader is true
+		if header == "Bcc" && email.AddBccToHeader {
+			email.headers.Add(header, address.String())
+		}
+
 		// add all addresses to the headers except for Bcc and Return-Path
 		if header != "Bcc" && header != "Return-Path" {
 			// add the address to the headers