Requests with bodies must have content-type of application/json

[xatxay]

When i used multipart to send a tweet i'd get 400 error saying {\"errors\":[{\"message\":\"Requests with bodies must have content-type of application/json.\"}],\"title\":\"Invalid Request\",\"detail\":\"One or more parameters to your request was invalid.\",\"type\":\"https://api.twitter.com/2/problems/invalid-request\"}

// this gave me the 400
let content = multipart::Form::new()
    .text("status", "Hello, Twitter!");
    
.multipart(content)

A work around i did was

let tweet_data = json!({"text": "hello"}).to_string();

.header("Content-Type", "application/json")
        .body(tweet_data)

just posting here in case someone run into this same issue.