in src/azure/client.rs [311:324]
fn write_headers(headers: &HeaderMap, dst: &mut Vec<u8>) {
for (name, value) in headers {
// We need special case handling here otherwise Azure returns 400
// due to `Content-Id` instead of `Content-ID`
if name == "content-id" {
extend(dst, b"Content-ID");
} else {
title_case(dst, name.as_str().as_bytes());
}
extend(dst, b": ");
extend(dst, value.as_bytes());
extend(dst, b"\r\n");
}
}