feat(client): set client buffer size to avoid buffer overflow

[GoldenSheep402]

In client.go

The origin code is:

	go func() {
		defer c.clientWaitGroup.Done()
		defer c.pipesWaitGroup.Done()
		defer close(linesCh)

		scanner := bufio.NewScanner(runner.Stdout())

		for scanner.Scan() {
			linesCh <- scanner.Text()
		}
		if scanner.Err() != nil {
			c.logger.Error("error encountered while scanning stdout", "error", scanner.Err())
		}
	}()

If runner.Stdout()is bigger than 64kb, it will cause [ERROR] plugin: error encountered while scanning stdout: error="bufio.Scanner: token too long"

A fixed version is:

	go func() {
		defer c.clientWaitGroup.Done()
		defer c.pipesWaitGroup.Done()
		defer close(linesCh)

		scanner := bufio.NewScanner(runner.Stdout())
		buf := make([]byte, c.config.ClientScanerBufferSize)
		scanner.Buffer(buf, c.config.ClientScanerBufferSize)

		for scanner.Scan() {
			linesCh <- scanner.Text()
		}
		if scanner.Err() != nil {
			c.logger.Error("error encountered while scanning stdout", "error", scanner.Err())
		}
	}()

The ClientScanerBufferSize is provided as a config item(default is 64KB), user can set it by themselves if their command will return a large output and avoid receiving a null result.

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