速度控制并不能精确的控制速度？

"speed": {
"channel": 5,
"byte": 1048576,
"record": 10000
}
速度控制设置并不是精确的控制速度，而是根据配置计算出一个合适的channel数，怎么才能精确的控制速度呢，比如record设置了500，读写记录速度就不超过500？
```
private void adjustChannelNumber() {
int needChannelNumberByByte = Integer.MAX_VALUE;
int needChannelNumberByRecord = Integer.MAX_VALUE;

boolean isByteLimit = (this.configuration.getInt(
CoreConstant.DATAX_JOB_SETTING_SPEED_BYTE, 0) > 0);
if (isByteLimit) {
long globalLimitedByteSpeed = this.configuration.getInt(
CoreConstant.DATAX_JOB_SETTING_SPEED_BYTE, 10 * 1024 * 1024);

// 在byte流控情况下，单个Channel流量最大值必须设置，否则报错！
Long channelLimitedByteSpeed = this.configuration
.getLong(CoreConstant.DATAX_CORE_TRANSPORT_CHANNEL_SPEED_BYTE);
if (channelLimitedByteSpeed == null || channelLimitedByteSpeed <= 0) {
DataXException.asDataXException(
FrameworkErrorCode.CONFIG_ERROR,
"在有总bps限速条件下，单个channel的bps值不能为空，也不能为非正数");
}

needChannelNumberByByte =
(int) (globalLimitedByteSpeed / channelLimitedByteSpeed);
needChannelNumberByByte =
needChannelNumberByByte > 0 ? needChannelNumberByByte : 1;
LOG.info("Job set Max-Byte-Speed to " + globalLimitedByteSpeed + " bytes.");
}

boolean isRecordLimit = (this.configuration.getInt(
CoreConstant.DATAX_JOB_SETTING_SPEED_RECORD, 0)) > 0;
if (isRecordLimit) {
long globalLimitedRecordSpeed = this.configuration.getInt(
CoreConstant.DATAX_JOB_SETTING_SPEED_RECORD, 100000);

Long channelLimitedRecordSpeed = this.configuration.getLong(
CoreConstant.DATAX_CORE_TRANSPORT_CHANNEL_SPEED_RECORD);
if (channelLimitedRecordSpeed == null || channelLimitedRecordSpeed <= 0) {
DataXException.asDataXException(FrameworkErrorCode.CONFIG_ERROR,
"在有总tps限速条件下，单个channel的tps值不能为空，也不能为非正数");
}

needChannelNumberByRecord =
(int) (globalLimitedRecordSpeed / channelLimitedRecordSpeed);
needChannelNumberByRecord =
needChannelNumberByRecord > 0 ? needChannelNumberByRecord : 1;
LOG.info("Job set Max-Record-Speed to " + globalLimitedRecordSpeed + " records.");
}

// 取较小值
this.needChannelNumber = needChannelNumberByByte < needChannelNumberByRecord ?
needChannelNumberByByte : needChannelNumberByRecord;

// 如果从byte或record上设置了needChannelNumber则退出
if (this.needChannelNumber < Integer.MAX_VALUE) {
return;
}

boolean isChannelLimit = (this.configuration.getInt(
CoreConstant.DATAX_JOB_SETTING_SPEED_CHANNEL, 0) > 0);
if (isChannelLimit) {
this.needChannelNumber = this.configuration.getInt(
CoreConstant.DATAX_JOB_SETTING_SPEED_CHANNEL);

LOG.info("Job set Channel-Number to " + this.needChannelNumber
+ " channels.");

return;
}

throw DataXException.asDataXException(
FrameworkErrorCode.CONFIG_ERROR,
"Job运行速度必须设置");
}
```

Start by tracing the adjustChannelNumber() logic shown in the issue and the speed configuration values for byte, record, and channel limits. Clarify how enforcement should behave when record is set to 500, then identify the relevant transport path and add tests showing that read and write throughput does not exceed the configured record rate.

Written by the indexing model from the issue text.