private void WriteFieldNameOrString()

in Microsoft.Azure.Cosmos/src/Json/JsonWriter.JsonBinaryWriter.cs [1376:1475]
87 lines of code
33 McCabe index (conditional complexity)

            private void WriteFieldNameOrString(bool isFieldName, Utf8Span utf8Span)
            {
                this.binaryWriter.EnsureRemainingBufferSpace(TypeMarkerLength + JsonBinaryEncoding.FourByteLength + utf8Span.Length);

                this.JsonObjectState.RegisterToken(isFieldName ? JsonTokenType.FieldName : JsonTokenType.String);
                if (JsonBinaryEncoding.TryGetEncodedStringTypeMarker(
                    utf8Span,
                    this.JsonObjectState.CurrentTokenType == JsonTokenType.FieldName ? this.jsonStringDictionary : null,
                    out JsonBinaryEncoding.MultiByteTypeMarker multiByteTypeMarker))
                {
                    switch (multiByteTypeMarker.Length)
                    {
                        case 1:
                            this.binaryWriter.Write(multiByteTypeMarker.One);
                            break;

                        case 2:
                            this.binaryWriter.Write(multiByteTypeMarker.One);
                            this.binaryWriter.Write(multiByteTypeMarker.Two);
                            break;

                        default:
                            throw new InvalidOperationException($"Unable to serialize a {nameof(JsonBinaryEncoding.MultiByteTypeMarker)} of length: {multiByteTypeMarker.Length}");
                    }
                }
                else if (this.enableEncodedStrings
                    && isFieldName
                    && (utf8Span.Length >= MinReferenceStringLength)
                    && this.TryRegisterStringValue(utf8Span))
                {
                    // Work is done in the check
                }
                else if (this.enableEncodedStrings
                    && !isFieldName
                    && (utf8Span.Length == JsonBinaryEncoding.GuidLength)
                    && JsonBinaryEncoding.TryEncodeGuidString(utf8Span.Span, this.binaryWriter.Cursor))
                {
                    // Encoded value as guid string
                    this.binaryWriter.Position += JsonBinaryEncoding.EncodedGuidLength;
                }
                else if (this.enableEncodedStrings
                    && !isFieldName
                    && (utf8Span.Length == JsonBinaryEncoding.GuidWithQuotesLength)
                    && (utf8Span.Span[0] == '"')
                    && (utf8Span.Span[JsonBinaryEncoding.GuidWithQuotesLength - 1] == '"')
                    && JsonBinaryEncoding.TryEncodeGuidString(utf8Span.Span.Slice(start: 1), this.binaryWriter.Cursor)
                    && (this.binaryWriter.Cursor[0] == TypeMarker.LowercaseGuidString))
                {
                    // Encoded value as lowercase double quote guid
                    this.binaryWriter.Cursor[0] = TypeMarker.DoubleQuotedLowercaseGuidString;
                    this.binaryWriter.Position += JsonBinaryEncoding.EncodedGuidLength;
                }
                else if (this.enableEncodedStrings
                    && !isFieldName
                    && JsonBinaryEncoding.TryEncodeCompressedString(utf8Span.Span, this.binaryWriter.Cursor, out int bytesWritten))
                {
                    // Encoded value as a compressed string
                    this.binaryWriter.Position += bytesWritten;
                }
                else if (this.enableEncodedStrings
                    && !isFieldName
                    && (utf8Span.Length >= MinReferenceStringLength)
                    && (utf8Span.Length <= MaxReferenceStringLength)
                    && this.TryRegisterStringValue(utf8Span))
                {
                    // Work is done in the check
                }
                else if (TypeMarker.TryGetEncodedStringLengthTypeMarker(utf8Span.Length, out byte typeMarker))
                {
                    // Write with type marker that encodes the length
                    this.binaryWriter.Write(typeMarker);
                    this.binaryWriter.Write(utf8Span.Span);
                }
                // Just write it out as a regular string with type marker and length prefix
                else if (utf8Span.Length < byte.MaxValue)
                {
                    this.binaryWriter.Write(TypeMarker.StrL1);
                    this.binaryWriter.Write((byte)utf8Span.Length);
                    this.binaryWriter.Write(utf8Span.Span);
                }
                else if (utf8Span.Length < ushort.MaxValue)
                {
                    this.binaryWriter.Write(TypeMarker.StrL2);
                    this.binaryWriter.Write((ushort)utf8Span.Length);
                    this.binaryWriter.Write(utf8Span.Span);
                }
                else
                {
                    // (utf8String.Length < uint.MaxValue)
                    this.binaryWriter.Write(TypeMarker.StrL4);
                    this.binaryWriter.Write((uint)utf8Span.Length);
                    this.binaryWriter.Write(utf8Span.Span);
                }

                if (!isFieldName)
                {
                    // If we just wrote a string then increment the count (we don't increment for field names, since we need to wait for the corresponding property value).
                    this.bufferedContexts.Peek().Count++;
                }
            }