in Sources/NIOTransportServices/NIOTSConnectionChannel.swift [99:107]
mutating func writabilityChanges(whenBytesSent sentBytes: Int) -> Bool {
self.outstandingBytes -= sentBytes
if self.outstandingBytes < self.waterMarks.low && !self.writable.load() {
self.writable.store(true)
return true
}
return false
}