addHeader method Null safety

void addHeader(
  1. String name,
  2. APIHeader header

Adds a header to headers for name.

If headers is null, it is created. If the key does not exist in headers, header is added for the key. If the key exists, header is not added. (To replace a header, access headers directly.)


void addHeader(String name, APIHeader header) {
  headers ??= {};
  if (!headers!.containsKey(name)) {
    headers![name] = header;