pub struct BufWriter<W> { /* private fields */ }
Expand description

Wraps a writer and buffers its output.

It can be excessively inefficient to work directly with something that implements AsyncWrite. A BufWriter keeps an in-memory buffer of data and writes it to an underlying writer in large, infrequent batches.

BufWriter can improve the speed of programs that make small and repeated write calls to the same file or network socket. It does not help when writing very large amounts at once, or writing just one or a few times. It also provides no advantage when writing to a destination that is in memory, like a Vec<u8>.

When the BufWriter is dropped, the contents of its buffer will be discarded. Creating multiple instances of a BufWriter on the same stream can cause data loss. If you need to write out the contents of its buffer, you must manually call flush before the writer is dropped.

Implementations

Creates a new BufWriter with a default buffer capacity. The default is currently 8 KB, but may change in the future.

Creates a new BufWriter with the specified buffer capacity.

Gets a reference to the underlying writer.

Gets a mutable reference to the underlying writer.

It is inadvisable to directly write to the underlying writer.

Gets a pinned mutable reference to the underlying writer.

It is inadvisable to directly write to the underlying writer.

Consumes this BufWriter, returning the underlying writer.

Note that any leftover data in the internal buffer is lost.

Returns a reference to the internally buffered data.

Trait Implementations

Attempts to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to poll_read. Read more

Attempts to read from the AsyncRead into buf. Read more

Seek to the offset, in bytes, in the underlying writer.

Seeking always writes out the internal buffer before seeking.

Attempts to seek to an offset, in bytes, in a stream. Read more

Waits for a seek operation to complete. Read more

Attempt to write bytes from buf into the object. Read more

Like poll_write, except that it writes from a slice of buffers. Read more

Determines if this writer has an efficient poll_write_vectored implementation. Read more

Attempts to flush the object, ensuring that any buffered data reach their destination. Read more

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down. Read more

Formats the value using the given formatter. Read more

Converts to this type from the input type.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.