Fetch the API streams

I wanted to try the elegance of the API you created, and I am happy what it provides , the thing is … .it works with curl but trying to use it with fetch I saw that I am dealing with streams I hope someone can help me understand why streams?
how to retrieve first meaningful result here is the code:

       method: 'POST',
       headers: {
         Accept: 'application/json',
         'Content-Type': 'application/json',
         'X-API-Key': process.env.MORALIS_API_KEY
       body: JSON.stringify({
         abi: abi,
     .then(response => response.body)
     .then(body => {
       const reader = body.getReader()

       reader.read().then(({ value, done }) => {
         const result = Utf8ArrayToStr(value)
         if (result) {

it should work somehow, as it is only a http request