serial: slow feed mode - fixes #4901

tabby-serial/src/api.ts

@@ -20,6 +20,7 @@ export interface SerialProfileOptions extends StreamProcessingOptions, LoginScri
     xon?: boolean
     xoff?: boolean
     xany?: boolean
+    slowSend?: boolean
 }
 
 export const BAUD_RATES = [
@@ -123,7 +124,13 @@ export class SerialSession extends BaseSession {
     }
 
     write (data: Buffer): void {
-        this.streamProcessor.feedFromTerminal(data)
+        if (!this.profile.options.slowSend) {
+            this.streamProcessor.feedFromTerminal(data)
+        } else {
+            for (const byte of data) {
+                this.streamProcessor.feedFromTerminal(Buffer.from([byte]))
+            }
+        }
     }
 
     async destroy (): Promise<void> {

tabby-serial/src/components/serialProfileSettings.component.pug

@@ -77,6 +77,12 @@ ul.nav-tabs(ngbNav, #nav='ngbNav')
                     .title Xany
                 toggle([(ngModel)]='profile.options.xany')
 
+            .form-line
+                .header
+                    .title Slow feed
+                    .description Sends data one byte at a time
+                toggle([(ngModel)]='profile.options.slowFeed')
+
     li(ngbNavItem)
         a(ngbNavLink) Login scripts
         ng-template(ngbNavContent)

tabby-serial/src/profiles.ts

@@ -30,6 +30,7 @@ export class SerialProfilesService extends ProfileProvider<SerialProfile> {
             inputNewlines: null,
             outputNewlines: null,
             scripts: [],
+            slowSend: false,
         },
     }