function GltfBufferBuilder(gltfBuilder, bufferIndex) {
  this.gltfBuilder = gltfBuilder;
  this.bufferIndex = bufferIndex;
  this.buffer = this.gltfBuilder.gltf.buffers[bufferIndex];
  this.viewBuilders = [];
}
A fluent interface for building a glTF buffer.
@param {GltfBuilder} gltfBuilder The glTF builder.
@param {number} bufferIndex The index of this buffer in the glTF.
@private