public interface io.reactivex.internal.fuseable.HasUpstreamCompletableSource
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: io.reactivex.internal.fuseable.HasUpstreamCompletableSource
  super_class: java.lang.Object
{
  public abstract io.reactivex.CompletableSource source();
    descriptor: ()Lio/reactivex/CompletableSource;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "HasUpstreamCompletableSource.java"