Unity: Mono StackFrame with 0 allocations

LeanStackFrameMono.cs

        private readonly struct FrameData : IEquatable<FrameData>
        {
            public readonly MethodBase method;
            public readonly int lineNumber;
            public readonly int columnNumber;
           
            // mono internal
            private static readonly MethodInfo get_frame_info_methodInfo 
                = typeof(StackFrame).GetMethod("get_frame_info", BindingFlags.Static | BindingFlags.NonPublic);

            private delegate bool get_frame_info(int depth, bool fileInfo, ref MethodBase methodBase,
                ref int offset, ref int ilOffset, ref string fileName, ref int lineNumber, ref int columnNumber);
            
            private static readonly get_frame_info get_frame_info_delegate 
                = (get_frame_info)Delegate.CreateDelegate(typeof(get_frame_info), get_frame_info_methodInfo);
            
            public FrameData(int depth) : this()
            {
                int offset = 0, ilOffset = 0;
                string fileName = null;
                get_frame_info_delegate(depth, false, ref method, ref offset, ref ilOffset, 
                    ref fileName, ref lineNumber, ref columnNumber);
            }

            public override string ToString()
            {
                var sb = new StringBuilder();
                if (method != null)
                {
                    if (method.DeclaringType != null) 
                        sb.Append(method.DeclaringType.FullName);
                    sb.Append(".");
                    sb.Append(method.Name);
                }
                else
                {
                    sb.Append("(unknown)");
                }

                if (lineNumber != 0)
                {
                    sb.Append(":");
                    sb.Append(lineNumber);
                }

                return sb.ToString();
            }

            public override int GetHashCode()
            {
                return HashCode.Combine(method, lineNumber, columnNumber);
            }

            public bool Equals(FrameData other)
            {
                return method == other.method && lineNumber == other.lineNumber && columnNumber == other.columnNumber;
            }

            public override bool Equals(object obj)
            {
                return obj is FrameData other && Equals(other);
            }
        }