add some doc comments

Signed-off-by: zyguan <[email protected]>

internal/client/client_batch.go

@@ -76,6 +76,7 @@ type batchCommandsEntry struct {
 	err      error
 	pri      uint64
 
+	// start indicates when the batch commands entry is generated and sent to the batch conn channel.
 	start   time.Time
 	sendLat int64
 	recvLat int64
@@ -389,6 +390,7 @@ func (a *batchConn) fetchMorePendingRequests(
 const idleTimeout = 3 * time.Minute
 
 var (
+	// presetBatchPolicies defines a set of [turboBatchOptions] as batch policies.
 	presetBatchPolicies = map[string]turboBatchOptions{
 		config.BatchPolicyBasic:    {},
 		config.BatchPolicyStandard: {V: turboBatchTimeBased, T: 0.0001, N: 5, W: 0.2, P: 0.8, Q: 0.8},
@@ -402,6 +404,7 @@ const (
 	turboBatchProbBased
 )
 
+// turboBatchOptions defines internal options for the [turboBatchTrigger].
 type turboBatchOptions struct {
 	V int     `json:"v"`
 	N int     `json:"n,omitempty"`
@@ -411,6 +414,21 @@ type turboBatchOptions struct {
 	Q float64 `json:"q,omitempty"`
 }
 
+// turboBatchTrigger is used to trigger the `fetchMorePendingRequests` dynamically according to the request arrival
+// intervals. The option `v` indicates the strategy of triggering:
+//
+//   - turboBatchAlways: always fetch more requests.
+//
+//   - turboBatchTimeBased: fetch more requests if estArrivalInterval < p * t
+//     where estArrivalInterval = w*reqArrivalInterval + (1-w)*estArrivalInterval
+//     and reqArrivalInterval = min(reqArrivalInterval, n * t)
+//
+//   - turboBatchProbBased: fetch more requests if estFetchMoreProb > p
+//     where estFetchMoreProb = w*thisProb + (1-w)*estFetchMoreProb
+//     and thisProb = reqArrivalInterval < t ? 1 : 0
+//
+// The option `q` is used to adjust the `batchWaitSize` dynamically. If the fractional part of the `avgBatchWaitSize` is
+// greater or equal to `q`, the `batchWaitSize` will be increased by 1.
 type turboBatchTrigger struct {
 	opts turboBatchOptions