fix errcheck and gocritic lint issue for exporter splunk

[fatsheep9146]

Signed-off-by: Ziqi Zhao zhaoziqi9146@gmail.com

Description:
fix gocritic and gocritic issue for splunk exporter

the code is modified as following

_, _ = state.tmpBuf.WriteTo(state.buf)

because in function makeBlankBufferState, the tmpBuf is already initialized with smaller spaces than buf

func makeBlankBufferState(bufCap uint) bufferState {
	// Buffer of JSON encoded Splunk events, last record is expected to overflow bufCap, hence the padding
	var buf = bytes.NewBuffer(make([]byte, 0, bufCap+bufCapPadding))

	// Buffer for overflown records that do not fit in the main buffer
	var tmpBuf = bytes.NewBuffer(make([]byte, 0, bufCapPadding))

	return bufferState{
		buf:      buf,
		tmpBuf:   tmpBuf,
		bufFront: nil, // Index of the log record of the first unsent event in buffer.
		bufLen:   0,   // Length of data in buffer excluding the last record if it overflows bufCap
		resource: 0,   // Index of currently processed Resource
		library:  0,   // Index of currently processed Library
	}
}

Link to tracking Issue:
#10466 #9749

[dashpole]

If those functions shouldn't ever return errors, why not check the error from those functions anyways? It seems like a generally a better practice to handle errors.

[fatsheep9146]

If those functions shouldn't ever return errors, why not check the error from those functions anyways? It seems like a generally a better practice to handle errors.

It makes sense, I will change like this.

[fatsheep9146]

ping @dashpole, please help review this again, thx

[fatsheep9146]

ping @bogdandrutu, please review this again, thanks.

[fatsheep9146]

ping @bogdandrutu @djaglowski, I think this pr is ready to be merged, please help review this pr, thanks.