docs: public MethodDescriptor getMethodDescriptor(@SlashedClassName String className, String name, String signature,
              boolean isStatic) {
          if (className == null) {
              throw new NullPointerException("className must be nonnull");
          }
          MethodDescriptor methodDescriptor = new MethodDescriptor(className, name, signature, isStatic);
          MethodDescriptor existing = methodDescriptorMap.get(methodDescriptor);
          if (existing == null) {
              methodDescriptorMap.put(methodDescriptor, methodDescriptor);
              existing = methodDescriptor;
          }
          return existing;
      }