type Config struct {
	URLs        []string `arg:"-u,env:urls,separate,required"` // example: -u http://localhost:8080 -u http://localhost:8081
	MaxRPS      int64    `arg:"env:MAX_RPS" default:"1000"`
	MinWorkers  int64    `arg:"env:MIN_WORKERS" default:"10"`
	MaxWorkers  int64    `arg:"env:MAX_WORKERS" default:"100"`
	MaxRequests int64    `arg:"env:MAX_REQUESTS"`

	// RequestHeaders add user request headers to each request (for example x-access-token).
	RequestHeaders map[string]string `arg:"-r,env:REQUEST_HEADERS"` // example: -r x-access-token=access-token x-country-code=us
	// AddTimestampToUrl is add unique timestamp in milliseconds value to each URL (commonly for avoid HTTP cache).
	AddTimestampToUrl bool `arg:"env:ADD_TIMESTAMP_TO_URL"`

	// Duration of application operation.
	Duration      string `arg:"env:DURATION" default:"1m"`
	DurationValue time.Duration

	// Stages is a number of parts by which will be separated output table.
	Stages int64 `arg:"-s,env:NUM_STAGES" default:"1"`
	// LogFile is a path to file into which will be redirected logs.
	LogFile string `arg:"-l,env:LOG_FILE"`
	// LogHeaders is a slice of headers which must be caught on request error.
	LogHeaders []string `arg:"-h,separate,env:CATCH_HEADERS"`
	// ExpectedResponseData is string which contains expected response data.
	// If it does not match, request will be marked as failed.
	ExpectedResponseData string `arg:"-e,env:EXPECTED_RESPONSE_DATA"`

	// PoolInitSize is httpclient pool init. size.
	PoolInitSize int64 `arg:"-i,env:HTTP_CLIENT_POOL_INIT_SIZE" default:"32"`
	// PoolMaxSize is httpclient pool max size.
	PoolMaxSize int64 `arg:"-m,env:HTTP_CLIENT_POOL_MAX_SIZE"   default:"10240"`

	// ToleranceCoefficient tell the application how much tolerance you can accept, since all values are very different
	// and achieving absolute results is very difficult (for example, due to network latency).
	// This will work as follows, for example, if we consider a strategy based on the average response time of
	// successful requests (spawn_by_avg_duration), then the calculation will be as follows:
	// average successful response time < target response time of successful requests * (1 - ToleranceCoefficient).
	// Example:
	// 	AvgSuccessResponseTime = 500ms
	//  TargetAvgSuccessRequestsDuration = 450ms
	//  AvgSuccessResponseTime * (1 - ToleranceCoefficient) = 450ms.
	// In this case, spawn will not continue.
	ToleranceCoefficient float64 `arg:"env:TOLERANCE_COEFFICIENT" default:"0.1"`

	// SpawnInterval is using for spawn_by_interval, spawn_by_avg_duration strategies.
	// It necessary for check the result of increasing/decreasing workers.
	SpawnInterval      string `arg:"-i,env:SPAWN_REQ_SENDER_INTERVAL" default:"1s"`
	SpawnIntervalValue time.Duration

	// TargetRPS used for spawn_by_rps strategy. If current RPS is under the target, spawn will be continued
	//	(used ToleranceCoefficient for determine aa space between from and to values).
	TargetRPS int64 `arg:"env:TARGET_RPS"`

	// TargetAvgSuccessRequestsDuration tells the target of average duration of success requests
	// which used into the spawn_by_avg_duration strategy.
	TargetAvgSuccessRequestsDuration      string        `arg:"env:TARGET_AVG_SUCCESS_REQUESTS_DURATION" default:"500ms"`
	TargetAvgSuccessRequestsDurationValue time.Duration // will contain the value after config parsing

	// SpawnVoteStrategy tells which approach will be used for spawn a new worker for send requests.
	// Options:
	// 	all 		 - means that all voters must vote for spawn a new worker.
	// 	many 		 - means that many voter must vote for spawn a new worker.
	// 	at_least_one - means that at least one voter must vote for spawn a new worker.
	SpawnVoteStrategy string `arg:"env:SPAWN_REQ_SENDER_STRATEGY" default:"at_least_one"`
	// CloseVoteStrategy tells which approach will be used for spawn a new worker for send requests.
	// Options:
	// 	all 		 - means that all voters must vote for close a worker.
	// 	many 		 - means that many voter must vote for close a worker.
	// 	at_least_one - means that at least one voter must vote for close a worker.
	CloseVoteStrategy string `arg:"env:CLOSE_REQ_SENDER_STRATEGY" default:"at_least_one"`

	// SpawnVoters tells which voters must be used for vote
	//	for spawn a new worker for send requests (allowed any combinations).
	//
	// Options:
	//	spawn_by_min_workers  	- for this case will be used MinWorkers configuration value.
	//		If number of active workers is under this value, them will spawn until it will not.
	//	spawn_by_rps			- for this case will be used current RPS (requests per second)
	//		for determine whether is necessary to spawn a new worker. For each 10 RPS will spawn a new worker.
	//	spawn_by_avg_duration 	- for this case will be use value of TargetAvgDuration (total reqs. duration / total reqs.).
	//		If the TargetAvgDuration is under the current average requests duration, the workers will be spawning.
	// 	spawn_by_interval	 	- for this case will be used SpawnInterval value.
	SpawnVoters []string `arg:"separate,env:REQ_SENDER_SPAWN_VOTERS"`
	// CloseVoters tells which voters must be used for vote
	//	for close a worker (allowed any combinations).
	//
	// Options:
	//	close_by_max_workers  - for this case will be used MinWorkers configuration value.
	//		If number of active workers is above this value, them will close one by one until it will not.
	//	close_by_rps			- for this case will be used current RPS (requests per second)
	//		for determine whether is necessary to close a worker.
	//		That is if the current RPS is above of (target RPS + 15%), the workers will be closing.
	//	close_by_avg_duration - for this case will be use value of TargetAvgDuration (total reqs. duration / total reqs.).
	//		If the TargetAvgDuration is above the current average requests duration, the workers will be closing.
	CloseVoters []string `arg:"separate,env:REQ_SENDER_CLOSE_VOTERS"`
}

go run cmd/main.go --url="http://0.0.0.0:8080/api/v1/stressed-endpoint" \
 --maxrps=1000 \
 --duration=10m \
 --maxworkers=10 --minworkers=10 \
 --poolinitsize=32 --poolmaxsize=1024