Support multithreaded uploads for faster transfers

[stanhu]

For large transfers, parallelizing Put Blob Block calls may speed up transfers significantly. This block of code could likely benefit:

azure-storage-ruby/blob/lib/azure/storage/blob/block.rb

Lines 464 to 497 in 0d3e5ac

	def create_block_blob_multiple_put(container, blob, content, size, options = {})
	content_type = get_or_apply_content_type(content, options[:content_type])
	content = StringIO.new(content) if content.is_a? String
	block_size = get_block_size(size)
	# Get the number of blocks
	block_count = (Float(size) / Float(block_size)).ceil
	block_list = []
	for block_id in 0...block_count
	id = block_id.to_s.rjust(6, "0")
	put_blob_block(container, blob, id, content.read(block_size), timeout: options[:timeout], lease_id: options[:lease_id])
	block_list.push([id])
	end
	# Commit the blocks put
	commit_options = {}
	commit_options[:content_type] = content_type
	commit_options[:content_encoding] = options[:content_encoding] if options[:content_encoding]
	commit_options[:content_language] = options[:content_language] if options[:content_language]
	commit_options[:content_md5] = options[:content_md5] if options[:content_md5]
	commit_options[:cache_control] = options[:cache_control] if options[:cache_control]
	commit_options[:content_disposition] = options[:content_disposition] if options[:content_disposition]
	commit_options[:metadata] = options[:metadata] if options[:metadata]
	commit_options[:timeout] = options[:timeout] if options[:timeout]
	commit_options[:request_id] = options[:request_id] if options[:request_id]
	commit_options[:lease_id] = options[:lease_id] if options[:lease_id]
	commit_blob_blocks(container, blob, block_list, commit_options)
	get_properties_options = {}
	get_properties_options[:lease_id] = options[:lease_id] if options[:lease_id]
	# Get the blob properties
	get_blob_properties(container, blob, get_properties_options)
	end

The Amazon SDK does something similar: https://github.com/aws/aws-sdk-ruby/blob/d2dc0213758da0aee100e485f2dfb090ffa7dbd5/gems/aws-sdk-s3/lib/aws-sdk-s3/multipart_file_uploader.rb#L133-L163

[katmsft]

Thanks for reporting. This repository also welcomes community contribution.