[client] Prevent to block channel writing (#3474)

The "runningChan" provides feedback to the UI or any client about whether the service is up and running. If the client exits earlier than when the service successfully starts, then this channel causes a block.

- Added timeout for reading the channel to ensure we don't cause blocks for too long for the caller
- Modified channel writing operations to be non-blocking

client/embed/embed.go

@@ -134,10 +134,11 @@ func (c *Client) Start(startCtx context.Context) error {
 
 	// either startup error (permanent backoff err) or nil err (successful engine up)
 	// TODO: make after-startup backoff err available
-	run := make(chan error, 1)
+	run := make(chan struct{}, 1)
+	clientErr := make(chan error, 1)
 	go func() {
 		if err := client.Run(run); err != nil {
-			run <- err
+			clientErr <- err
 		}
 	}()
 
@@ -147,13 +148,9 @@ func (c *Client) Start(startCtx context.Context) error {
 			return fmt.Errorf("stop error after context done. Stop error: %w. Context done: %w", stopErr, startCtx.Err())
 		}
 		return startCtx.Err()
-	case err := <-run:
-		if err != nil {
-			if stopErr := client.Stop(); stopErr != nil {
-				return fmt.Errorf("stop error after failed to startup. Stop error: %w. Start error: %w", stopErr, err)
-			}
-			return fmt.Errorf("startup: %w", err)
-		}
+	case err := <-clientErr:
+		return fmt.Errorf("startup: %w", err)
+	case <-run:
 	}
 
 	c.connect = client