https://openjdk.java.net/ 
interface jdk.internal.net.http.hpack.HPACK$BufferUpdateConsumer
  minor version: 0
  major version: 59
  flags: flags: (0x0600) ACC_INTERFACE, ACC_ABSTRACT
  this_class: jdk.internal.net.http.hpack.HPACK$BufferUpdateConsumer
  super_class: java.lang.Object
{
  public abstract void accept(long, int);
    descriptor: (JI)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      data  
      len   
}
SourceFile: "HPACK.java"
NestHost: jdk.internal.net.http.hpack.HPACK
InnerClasses:
  abstract BufferUpdateConsumer = jdk.internal.net.http.hpack.HPACK$BufferUpdateConsumer of jdk.internal.net.http.hpack.HPACK
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()