public interface IBufferBuilder
{
    int ValueLength { get; }
    Memory<byte> Memory { get; }
        
    int ValueBitSize { get; }
    int Capacity { get; }

    void AppendBit(bool bit);

    void AppendBits(ReadOnlySpan<bool> bits);
    void AppendBits(ReadOnlySpan<bool> bits, int length);

    void AppendByte(byte byteValue);
    void AppendByte(byte byteValue, int length);

    void AppendBytes(ReadOnlySpan<byte> bytes);
    void AppendBytes(ReadOnlySpan<byte> bytes, int length);
        
    /// <summary>
    /// Reserve a given number of items' additional capacity.
    /// </summary>
    /// <param name="additionalCapacity">Number of items of required additional capacity.</param>
    void Reserve(int additionalCapacity);

    /// <summary>
    /// Resize the buffer to a given size.
    /// </summary>
    /// <remarks>
    /// Note that if the required capacity is larger than the current length of the populated buffer so far,
    /// the buffer's contents in the new, expanded region are undefined.
    /// </remarks>
    /// <remarks>
    /// Note that if the required capacity is smaller than the current length of the populated buffer so far,
    /// the buffer will be truncated and items at the end of the buffer will be lost.
    /// </remarks>
    /// <param name="capacity">Number of items of required capacity.</param>
    void Resize(int capacity);

    /// <summary>
    /// Clear all contents appended so far.
    /// </summary>
    void Clear();

    /// <summary>
    /// Build an Arrow buffer from the appended contents so far.
    /// </summary>
    /// <param name="allocator">Optional memory allocator.</param>
    /// <returns>Returns an <see cref="ArrowBuffer"/> object.</returns>
    ArrowBuffer Build(MemoryAllocator allocator = default);

    /// <summary>
    /// Build an Arrow buffer from the appended contents so far of the specified byte size.
    /// </summary>
    /// <param name="allocator">Optional memory allocator.</param>
    /// <returns>Returns an <see cref="ArrowBuffer"/> object.</returns>
    ArrowBuffer Build(int byteSize, MemoryAllocator allocator = default);
}

public interface IStructBufferBuilder<T> : IBufferBuilder where T : struct
{
    void AppendNull();
    void AppendValue(T value);
    void AppendValues(ReadOnlySpan<T> values);
}