message: Adding stream guards
diff: @@ -20,6 +20,7 @@ extern "C" {
  #define ARROW_FLAG_MAP_KEYS_SORTED 4
  #ifndef ARROW_C_DATA_H
  +#define ARROW_C_DATA_H
  struct ArrowSchema {
  // Array type description
  const char *format;
  @@ -52,7 +53,10 @@ struct ArrowArray {
  // Opaque producer-specific data
  void *private_data;
  };
  +#endif
  +#ifndef ARROW_C_STREAM_INTERFACE
  +#define ARROW_C_STREAM_INTERFACE
  // EXPERIMENTAL
  struct ArrowArrayStream {
  // Callback to get the stream type
  