function GltfMeshBuilder(gltfBuilder, meshIndex) {
  this.gltfBuilder = gltfBuilder;
  this.meshIndex = meshIndex;
  this.mesh = gltfBuilder.gltf.meshes[this.meshIndex];
}
A fluent interface for building a glTF mesh.
@param {GltfBuilder} gltfBuilder The glTF builder.
@param {number} meshIndex The index of this mesh within the glTF.
@private