收集大型字符串的KotlinFlow太慢

提高性能的解决方案是使用BufferedWriter将大字符串分块写入文件。代码示例如下：

import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.withContext
import java.io.BufferedWriter
import java.io.File
import java.io.FileWriter
import java.io.IOException

suspend fun collectStrings(strings: Flow<String>, file: File) {
    val bufferSize = 8192 // 调整缓存大小以优化性能
    withContext(Dispatchers.IO) {
        BufferedWriter(FileWriter(file)).use { writer ->
            strings.collect { string ->
                try {
                    chunkedWrite(writer, string, bufferSize)
                } catch (e: IOException) {
                    e.printStackTrace()
                }
            }
        }
    }
}

@Throws(IOException::class)
private fun chunkedWrite(
    writer: BufferedWriter,
    string: String,
    bufferSize: Int
) {
    val length = string.length
    var index = 0
    while (index < length) {
        val endIndex = index + bufferSize
        if (endIndex < length) {
            writer.write(string.substring(index, endIndex))
        } else {
            writer.write(string.substring(index, length))
        }
        index += bufferSize
    }
}