// https://developer.chrome.com/articles/fetch-streaming-requests/#feature-detection export const isSupportNativeFetchStream = () => { const supportsRequestStreams = (() => { let duplexAccessed = false const params = { body: new ReadableStream(), method: 'POST', get duplex() { duplexAccessed = true return 'half' }, } const hasContentType = new Request('', params).headers.has('Content-Type') return duplexAccessed && !hasContentType })() return supportsRequestStreams }